<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with WebFilings-->
<!-- -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ComprehensiveIncomeChangesInComponentsOfAccumulatedOtherComprehensiveLossItemsDetails" xlink:href="ayi-20121130.xsd#ComprehensiveIncomeChangesInComponentsOfAccumulatedOtherComprehensiveLossItemsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ConsolidatedBalanceSheets" xlink:href="ayi-20121130.xsd#ConsolidatedBalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:href="ayi-20121130.xsd#ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ConsolidatedStatementsOfCashFlows" xlink:href="ayi-20121130.xsd#ConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:href="ayi-20121130.xsd#ConsolidatedStatementsOfComprehensiveIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/ConsolidatedStatementsOfIncome" xlink:href="ayi-20121130.xsd#ConsolidatedStatementsOfIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/DebtDetails" xlink:href="ayi-20121130.xsd#DebtDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/EarningsPerShareDetails" xlink:href="ayi-20121130.xsd#EarningsPerShareDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/FairValueMeasurementsDetails" xlink:href="ayi-20121130.xsd#FairValueMeasurementsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/PensionAndProfitSharingPlansDetails" xlink:href="ayi-20121130.xsd#PensionAndProfitSharingPlansDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SpecialChargeDetails" xlink:href="ayi-20121130.xsd#SpecialChargeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsBalanceSheetsDetails" xlink:href="ayi-20121130.xsd#SupplementalGuarantorCondensedConsolidatingFinancialStatementsBalanceSheetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsCashFlowsDetails" xlink:href="ayi-20121130.xsd#SupplementalGuarantorCondensedConsolidatingFinancialStatementsCashFlowsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsIncomeDetails" xlink:href="ayi-20121130.xsd#SupplementalGuarantorCondensedConsolidatingFinancialStatementsIncomeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsOtherComprehensiveIncomeDetails" xlink:href="ayi-20121130.xsd#SupplementalGuarantorCondensedConsolidatingFinancialStatementsOtherComprehensiveIncomeDetails" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ComprehensiveIncomeChangesInComponentsOfAccumulatedOtherComprehensiveLossItemsDetails" xlink:type="extended">
    <link:loc xlink:href="ayi-20121130.xsd#ayi_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:label="loc_ayi_AccumulatedOtherComprehensiveIncomeLossLineItems_D0F05399ABE9BDFBDB400235BE8EA0AB" xlink:type="locator" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_AccumulatedOtherComprehensiveIncomeLossTable" xlink:label="loc_ayi_AccumulatedOtherComprehensiveIncomeLossTable_4FE3FF590AE354205E270235BE8E0A5B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ayi_AccumulatedOtherComprehensiveIncomeLossLineItems_D0F05399ABE9BDFBDB400235BE8EA0AB" xlink:to="loc_ayi_AccumulatedOtherComprehensiveIncomeLossTable_4FE3FF590AE354205E270235BE8E0A5B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_A9B7390E49C67DFBF0380235BE8EDCE3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ayi_AccumulatedOtherComprehensiveIncomeLossTable_4FE3FF590AE354205E270235BE8E0A5B" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_A9B7390E49C67DFBF0380235BE8EDCE3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_7F50C909B8B9C5F1F0010235BE8E546D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_A9B7390E49C67DFBF0380235BE8EDCE3" xlink:to="loc_us-gaap_EquityComponentDomain_7F50C909B8B9C5F1F0010235BE8E546D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_7F50C909B8B9C5F1F0010235BE8E546D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_A9B7390E49C67DFBF0380235BE8EDCE3" xlink:to="loc_us-gaap_EquityComponentDomain_7F50C909B8B9C5F1F0010235BE8E546D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_72AB8313F19BD71A8BC60235BE8E38CC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_7F50C909B8B9C5F1F0010235BE8E546D" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_72AB8313F19BD71A8BC60235BE8E38CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedTranslationAdjustmentMember" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_BC8BC5314803C0B678900235BE8E77F6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_72AB8313F19BD71A8BC60235BE8E38CC" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_BC8BC5314803C0B678900235BE8E77F6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_F21C0672C7B60B97C2A80235BE8EDF66" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_72AB8313F19BD71A8BC60235BE8E38CC" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_F21C0672C7B60B97C2A80235BE8EDF66" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_785E2BFBC27C100700020235BE8FBDBE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ayi_AccumulatedOtherComprehensiveIncomeLossLineItems_D0F05399ABE9BDFBDB400235BE8EA0AB" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_785E2BFBC27C100700020235BE8FBDBE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_8D18B997DC421372DDF90235BE8FEF96" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ayi_AccumulatedOtherComprehensiveIncomeLossLineItems_D0F05399ABE9BDFBDB400235BE8EA0AB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_8D18B997DC421372DDF90235BE8FEF96" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ConsolidatedBalanceSheets" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_F32C60B42BBC4545900615A3D7870763" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_71187A86AB74BA7A430915A3D786B9BA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_F32C60B42BBC4545900615A3D7870763" xlink:to="loc_us-gaap_StatementTable_71187A86AB74BA7A430915A3D786B9BA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_99349CB5C158A113D25A15A3D7869832" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_71187A86AB74BA7A430915A3D786B9BA" xlink:to="loc_dei_LegalEntityAxis_99349CB5C158A113D25A15A3D7869832" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_49DB97ED5098AB5A353B15A3D787AE21_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_99349CB5C158A113D25A15A3D7869832" xlink:to="loc_dei_EntityDomain_49DB97ED5098AB5A353B15A3D787AE21_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_49DB97ED5098AB5A353B15A3D787AE21" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_99349CB5C158A113D25A15A3D7869832" xlink:to="loc_dei_EntityDomain_49DB97ED5098AB5A353B15A3D787AE21" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_C1C8B1F088FB19F558BE15A3D78781CC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F32C60B42BBC4545900615A3D7870763" xlink:to="loc_us-gaap_AssetsAbstract_C1C8B1F088FB19F558BE15A3D78781CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract_6473436FB0F6C4EACDA815A3D787EF5C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_C1C8B1F088FB19F558BE15A3D78781CC" xlink:to="loc_us-gaap_AssetsCurrentAbstract_6473436FB0F6C4EACDA815A3D787EF5C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_9A24B2A7FFC627B1CDE615A3D788C162" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_6473436FB0F6C4EACDA815A3D787EF5C" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_9A24B2A7FFC627B1CDE615A3D788C162" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_DDD2EF7C802712D7BA4215A3D788213D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_6473436FB0F6C4EACDA815A3D787EF5C" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_DDD2EF7C802712D7BA4215A3D788213D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_48A6F9EE75642EE98DAF15A3D7887072" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_6473436FB0F6C4EACDA815A3D787EF5C" xlink:to="loc_us-gaap_InventoryNet_48A6F9EE75642EE98DAF15A3D7887072" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DeferredTaxAssetsNetCurrent" xlink:label="loc_us-gaap_DeferredTaxAssetsNetCurrent_F00DB8E7D212601CD5A615A3D788267E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_6473436FB0F6C4EACDA815A3D787EF5C" xlink:to="loc_us-gaap_DeferredTaxAssetsNetCurrent_F00DB8E7D212601CD5A615A3D788267E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_C189CDA02335371763D215A3D788B2B8" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_6473436FB0F6C4EACDA815A3D787EF5C" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_C189CDA02335371763D215A3D788B2B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_237045F44B3E01EC83B015A3D7883FC2" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_6473436FB0F6C4EACDA815A3D787EF5C" xlink:to="loc_us-gaap_AssetsCurrent_237045F44B3E01EC83B015A3D7883FC2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNetAbstract" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_0AC67D8DB104B86667EC15A3D788D78A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_C1C8B1F088FB19F558BE15A3D78781CC" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_0AC67D8DB104B86667EC15A3D788D78A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Land" xlink:label="loc_us-gaap_Land_70EE4BBD027923C409DE15A3D7889E32" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_0AC67D8DB104B86667EC15A3D788D78A" xlink:to="loc_us-gaap_Land_70EE4BBD027923C409DE15A3D7889E32" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BuildingsAndImprovementsGross" xlink:label="loc_us-gaap_BuildingsAndImprovementsGross_26EE25811735288CCCB815A3D7889225" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_0AC67D8DB104B86667EC15A3D788D78A" xlink:to="loc_us-gaap_BuildingsAndImprovementsGross_26EE25811735288CCCB815A3D7889225" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MachineryAndEquipmentGross" xlink:label="loc_us-gaap_MachineryAndEquipmentGross_304B543383AF07DB126315A3D788498B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_0AC67D8DB104B86667EC15A3D788D78A" xlink:to="loc_us-gaap_MachineryAndEquipmentGross_304B543383AF07DB126315A3D788498B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_3CB9A355D7BF450B092B15A3D7880A25" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_0AC67D8DB104B86667EC15A3D788D78A" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_3CB9A355D7BF450B092B15A3D7880A25" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_D41D847444CD910203E015A3D7886A96" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_0AC67D8DB104B86667EC15A3D788D78A" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_D41D847444CD910203E015A3D7886A96" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_7C655B842D705AD8C84E15A3D788AD71" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetAbstract_0AC67D8DB104B86667EC15A3D788D78A" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_7C655B842D705AD8C84E15A3D788AD71" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsNoncurrentAbstract" xlink:label="loc_us-gaap_AssetsNoncurrentAbstract_B06A41BD984AF4A84BE415A3D7882EF5" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_C1C8B1F088FB19F558BE15A3D78781CC" xlink:to="loc_us-gaap_AssetsNoncurrentAbstract_B06A41BD984AF4A84BE415A3D7882EF5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_932F2EB6366DC541218215A3D789F327" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_B06A41BD984AF4A84BE415A3D7882EF5" xlink:to="loc_us-gaap_Goodwill_932F2EB6366DC541218215A3D789F327" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_57C54E87AADB104684E015A3D7897338" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_B06A41BD984AF4A84BE415A3D7882EF5" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_57C54E87AADB104684E015A3D7897338" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DeferredTaxAssetsNetNoncurrent" xlink:label="loc_us-gaap_DeferredTaxAssetsNetNoncurrent_BEF744379A20775D9C0B15A3D78994EA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_B06A41BD984AF4A84BE415A3D7882EF5" xlink:to="loc_us-gaap_DeferredTaxAssetsNetNoncurrent_BEF744379A20775D9C0B15A3D78994EA" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_OtherLongTermAssets" xlink:label="loc_ayi_OtherLongTermAssets_AD27DCFD3A1C8D8E007315A3D78910D2" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_B06A41BD984AF4A84BE415A3D7882EF5" xlink:to="loc_ayi_OtherLongTermAssets_AD27DCFD3A1C8D8E007315A3D78910D2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsNoncurrent" xlink:label="loc_us-gaap_AssetsNoncurrent_2CCC164C1AB0B5CD126415A3D789D7AB" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract_B06A41BD984AF4A84BE415A3D7882EF5" xlink:to="loc_us-gaap_AssetsNoncurrent_2CCC164C1AB0B5CD126415A3D789D7AB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_E406345E813D9990B30115A3D7896363" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_C1C8B1F088FB19F558BE15A3D78781CC" xlink:to="loc_us-gaap_Assets_E406345E813D9990B30115A3D7896363" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_737CE30B3C5F37638FE715A3D789654C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_F32C60B42BBC4545900615A3D7870763" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_737CE30B3C5F37638FE715A3D789654C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_3CDD67D619D4B7A3F3F015A3D78AD5BD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_737CE30B3C5F37638FE715A3D789654C" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_3CDD67D619D4B7A3F3F015A3D78AD5BD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_BD7EDD73FB87B04BA72015A3D78AF3B3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_3CDD67D619D4B7A3F3F015A3D78AD5BD" xlink:to="loc_us-gaap_AccountsPayableCurrent_BD7EDD73FB87B04BA72015A3D78AF3B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_0C7E2A8101E2CB8E0A9415A3D78AEA79" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_3CDD67D619D4B7A3F3F015A3D78AD5BD" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_0C7E2A8101E2CB8E0A9415A3D78AEA79" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_25602866C4BACD49540615A3D78A3452" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_3CDD67D619D4B7A3F3F015A3D78AD5BD" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_25602866C4BACD49540615A3D78A3452" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherAccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent_EAA7589A34E2EAC4C87915A3D78AF375" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_3CDD67D619D4B7A3F3F015A3D78AD5BD" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesCurrent_EAA7589A34E2EAC4C87915A3D78AF375" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_8F9E04DA97961B749A7C15A3D78A7158" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_3CDD67D619D4B7A3F3F015A3D78AD5BD" xlink:to="loc_us-gaap_LiabilitiesCurrent_8F9E04DA97961B749A7C15A3D78A7158" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_6A66E0E60E9714DA224415A3D78A9DCF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_737CE30B3C5F37638FE715A3D789654C" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_6A66E0E60E9714DA224415A3D78A9DCF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_DC39243FCCAC8787C48815A3D78A444A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_737CE30B3C5F37638FE715A3D789654C" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_DC39243FCCAC8787C48815A3D78A444A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DeferredTaxLiabilitiesNoncurrent" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesNoncurrent_6CA374B88ECF22710B5815A3D78A03C1" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_737CE30B3C5F37638FE715A3D789654C" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesNoncurrent_6CA374B88ECF22710B5815A3D78A03C1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SelfInsuranceReserveNoncurrent" xlink:label="loc_us-gaap_SelfInsuranceReserveNoncurrent_123414825369ECAEE3E315A3D78A4345" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_737CE30B3C5F37638FE715A3D789654C" xlink:to="loc_us-gaap_SelfInsuranceReserveNoncurrent_123414825369ECAEE3E315A3D78A4345" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_108AF1F6653CB4FF3A3F15A3D78ADB79" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_737CE30B3C5F37638FE715A3D789654C" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_108AF1F6653CB4FF3A3F15A3D78ADB79" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_E1422A84DD750786C6EB15A3D78ACEBA" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_737CE30B3C5F37638FE715A3D789654C" xlink:to="loc_us-gaap_CommitmentsAndContingencies_E1422A84DD750786C6EB15A3D78ACEBA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="loc_us-gaap_StockholdersEquityAbstract_6800419953F6EF9CC38315A3D78A442B" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_737CE30B3C5F37638FE715A3D789654C" xlink:to="loc_us-gaap_StockholdersEquityAbstract_6800419953F6EF9CC38315A3D78A442B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaap_PreferredStockValue_4D47F7F5D110957065EC15A3D78AFDF1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_6800419953F6EF9CC38315A3D78A442B" xlink:to="loc_us-gaap_PreferredStockValue_4D47F7F5D110957065EC15A3D78AFDF1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaap_CommonStockValue_7BDFB103AA189B047F9015A3D78BE434" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_6800419953F6EF9CC38315A3D78A442B" xlink:to="loc_us-gaap_CommonStockValue_7BDFB103AA189B047F9015A3D78BE434" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_BA91CAC5603117AB359215A3D78B6CD2" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_6800419953F6EF9CC38315A3D78A442B" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_BA91CAC5603117AB359215A3D78B6CD2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_8D8A896E6138DC1702CD15A3D78B60B1" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_6800419953F6EF9CC38315A3D78A442B" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_8D8A896E6138DC1702CD15A3D78B60B1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_389A5AC7833511846EF515A3D78BD7C3" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_6800419953F6EF9CC38315A3D78A442B" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_389A5AC7833511846EF515A3D78BD7C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TreasuryStockValue" xlink:label="loc_us-gaap_TreasuryStockValue_8B4627D14E71B933306015A3D78BD5AF" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_6800419953F6EF9CC38315A3D78A442B" xlink:to="loc_us-gaap_TreasuryStockValue_8B4627D14E71B933306015A3D78BD5AF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_1AAC92247DACF34F118C15A3D78BA8AC" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_6800419953F6EF9CC38315A3D78A442B" xlink:to="loc_us-gaap_StockholdersEquity_1AAC92247DACF34F118C15A3D78BA8AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_07A03C80642F4765B0D015A3D78B12E9" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_737CE30B3C5F37638FE715A3D789654C" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_07A03C80642F4765B0D015A3D78B12E9" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_53AFD0F475512EE21DD00235BED83896" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_0E6CC90DD003EBCC26560235BED81EC5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_53AFD0F475512EE21DD00235BED83896" xlink:to="loc_us-gaap_StatementTable_0E6CC90DD003EBCC26560235BED81EC5" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_944FA7830A61A61629D20235BED8032C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0E6CC90DD003EBCC26560235BED81EC5" xlink:to="loc_us-gaap_StatementScenarioAxis_944FA7830A61A61629D20235BED8032C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_71C4BBC47308B920A5280235BED85591_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_944FA7830A61A61629D20235BED8032C" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_71C4BBC47308B920A5280235BED85591_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_71C4BBC47308B920A5280235BED85591" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_944FA7830A61A61629D20235BED8032C" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_71C4BBC47308B920A5280235BED85591" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_7E31CBDC952C265AE6200235BED82CC8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_53AFD0F475512EE21DD00235BED83896" xlink:to="loc_us-gaap_AssetsAbstract_7E31CBDC952C265AE6200235BED82CC8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract_A3CBC53801C5DE8CAA6E0235BED8A4CC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_7E31CBDC952C265AE6200235BED82CC8" xlink:to="loc_us-gaap_AssetsCurrentAbstract_A3CBC53801C5DE8CAA6E0235BED8A4CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_591F4E606E9A6C75AC760235BED95015" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_A3CBC53801C5DE8CAA6E0235BED8A4CC" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_591F4E606E9A6C75AC760235BED95015" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_48EFC71073252858C8C70235BED93C5C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_53AFD0F475512EE21DD00235BED83896" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_48EFC71073252858C8C70235BED93C5C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="loc_us-gaap_StockholdersEquityAbstract_EB26A4384AB4BF4237820235BED97CB9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_48EFC71073252858C8C70235BED93C5C" xlink:to="loc_us-gaap_StockholdersEquityAbstract_EB26A4384AB4BF4237820235BED97CB9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_2D9F94AFDE9DCBF635980235BED905B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_EB26A4384AB4BF4237820235BED97CB9" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_2D9F94AFDE9DCBF635980235BED905B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_862EFFC48FD0245D8D390235BED95F60" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_EB26A4384AB4BF4237820235BED97CB9" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_862EFFC48FD0245D8D390235BED95F60" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="loc_us-gaap_PreferredStockSharesIssued_6A276CD1A2969C320A310235BED9D259" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_EB26A4384AB4BF4237820235BED97CB9" xlink:to="loc_us-gaap_PreferredStockSharesIssued_6A276CD1A2969C320A310235BED9D259" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_1A0424C20BC6D29FBC760235BED96019" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_EB26A4384AB4BF4237820235BED97CB9" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_1A0424C20BC6D29FBC760235BED96019" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_EE24B57EAA30A970EBCE0235BED92E3E" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_EB26A4384AB4BF4237820235BED97CB9" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_EE24B57EAA30A970EBCE0235BED92E3E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaap_CommonStockSharesIssued_493399E40A2561920BE90235BED9153E" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_EB26A4384AB4BF4237820235BED97CB9" xlink:to="loc_us-gaap_CommonStockSharesIssued_493399E40A2561920BE90235BED9153E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_2128A71E571E650AFC920235BED9DB6D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_EB26A4384AB4BF4237820235BED97CB9" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_2128A71E571E650AFC920235BED9DB6D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TreasuryStockShares" xlink:label="loc_us-gaap_TreasuryStockShares_C1B01C1DC6924E9908760235BED93E52" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_EB26A4384AB4BF4237820235BED97CB9" xlink:to="loc_us-gaap_TreasuryStockShares_C1B01C1DC6924E9908760235BED93E52" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_B7217310CD3D59ACBD0217C2BB3FE1F7" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_1D2DB6794BA902C1F38017C2BB3F9F9B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_B7217310CD3D59ACBD0217C2BB3FE1F7" xlink:to="loc_us-gaap_StatementTable_1D2DB6794BA902C1F38017C2BB3F9F9B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_2BE303D923B292FA5E9817C2BB3FC248" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1D2DB6794BA902C1F38017C2BB3F9F9B" xlink:to="loc_dei_LegalEntityAxis_2BE303D923B292FA5E9817C2BB3FC248" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_56326BCAD32AD82F577617C2BB3FE024_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_2BE303D923B292FA5E9817C2BB3FC248" xlink:to="loc_dei_EntityDomain_56326BCAD32AD82F577617C2BB3FE024_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_56326BCAD32AD82F577617C2BB3FE024" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_2BE303D923B292FA5E9817C2BB3FC248" xlink:to="loc_dei_EntityDomain_56326BCAD32AD82F577617C2BB3FE024" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_B7A85775F33B409A7D6017C2BB3F3E4A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B7217310CD3D59ACBD0217C2BB3FE1F7" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_B7A85775F33B409A7D6017C2BB3F3E4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_5C0E025D869707CF855D17C2BB3FCA28" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_B7A85775F33B409A7D6017C2BB3F3E4A" xlink:to="loc_us-gaap_NetIncomeLoss_5C0E025D869707CF855D17C2BB3FCA28" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36C13F9B1B51319641C017C2BB400E00" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_B7A85775F33B409A7D6017C2BB3F3E4A" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36C13F9B1B51319641C017C2BB400E00" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_9E1544D1B461170D2CC317C2BB40D5D8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36C13F9B1B51319641C017C2BB400E00" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_9E1544D1B461170D2CC317C2BB40D5D8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_B3357161C53B4586B47B17C2BB450068" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36C13F9B1B51319641C017C2BB400E00" xlink:to="loc_us-gaap_ShareBasedCompensation_B3357161C53B4586B47B17C2BB450068" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities" xlink:label="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities_2A8AB0BAE79A5A685AB117C2BB45CD92" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36C13F9B1B51319641C017C2BB400E00" xlink:to="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities_2A8AB0BAE79A5A685AB117C2BB45CD92" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:label="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_3521A210B716F1E0C01417C2BB469267" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36C13F9B1B51319641C017C2BB400E00" xlink:to="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_3521A210B716F1E0C01417C2BB469267" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DeferredIncomeTaxesAndTaxCredits" xlink:label="loc_us-gaap_DeferredIncomeTaxesAndTaxCredits_67E7C6D0345EE53FCB0A17C2BB466305" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36C13F9B1B51319641C017C2BB400E00" xlink:to="loc_us-gaap_DeferredIncomeTaxesAndTaxCredits_67E7C6D0345EE53FCB0A17C2BB466305" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_BABA829A64C937454B8017C2BB48B613" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36C13F9B1B51319641C017C2BB400E00" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_BABA829A64C937454B8017C2BB48B613" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_383FA66DE0783359E44717C2BB4892D4" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36C13F9B1B51319641C017C2BB400E00" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_383FA66DE0783359E44717C2BB4892D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_7757A89C44D1EE4A893817C2BB4822B0" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36C13F9B1B51319641C017C2BB400E00" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_7757A89C44D1EE4A893817C2BB4822B0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_C9C8F748CF430D21825217C2BB49843A" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36C13F9B1B51319641C017C2BB400E00" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_C9C8F748CF430D21825217C2BB49843A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInOtherAccruedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherAccruedLiabilities_AF110528D0F78E0E1F6B17C2BB4941F5" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36C13F9B1B51319641C017C2BB400E00" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherAccruedLiabilities_AF110528D0F78E0E1F6B17C2BB4941F5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_F5AE14575A1E8DC706EF17C2BB4905B4" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_36C13F9B1B51319641C017C2BB400E00" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_F5AE14575A1E8DC706EF17C2BB4905B4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_FAA58B721D02D94BEF3917C2BB4927E5" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_B7A85775F33B409A7D6017C2BB3F3E4A" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_FAA58B721D02D94BEF3917C2BB4927E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_EC894BE663BD8A50F31617C2BB49C992" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B7217310CD3D59ACBD0217C2BB3FE1F7" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_EC894BE663BD8A50F31617C2BB49C992" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_D001236AC04EF222559C17C2BB4A66F2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_EC894BE663BD8A50F31617C2BB49C992" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_D001236AC04EF222559C17C2BB4A66F2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" xlink:label="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_B59CBC6CA852C287C68017C2BB4A50FF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_EC894BE663BD8A50F31617C2BB49C992" xlink:to="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_B59CBC6CA852C287C68017C2BB4A50FF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_AD27B3C49546FE63B8BC17C2BB4A4168" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_EC894BE663BD8A50F31617C2BB49C992" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_AD27B3C49546FE63B8BC17C2BB4A4168" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_11F2AA0122D65208951717C2BB4A02AB" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_EC894BE663BD8A50F31617C2BB49C992" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_11F2AA0122D65208951717C2BB4A02AB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_C280F5E710E1535DB84417C2BB4A939F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B7217310CD3D59ACBD0217C2BB3FE1F7" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_C280F5E710E1535DB84417C2BB4A939F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_F931B30F345222DD833617C2BB4BFE4E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_C280F5E710E1535DB84417C2BB4A939F" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_F931B30F345222DD833617C2BB4BFE4E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_CED0A9F99A45C858626317C2BB4BB8AC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_C280F5E710E1535DB84417C2BB4A939F" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_CED0A9F99A45C858626317C2BB4BB8AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:label="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_A4B5846D32BC0F4D2D3C17C2BB4BC2CC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_C280F5E710E1535DB84417C2BB4A939F" xlink:to="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_A4B5846D32BC0F4D2D3C17C2BB4BC2CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsOfDividendsCommonStock" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock_B3A789E83E027F59705017C2BB4B6961" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_C280F5E710E1535DB84417C2BB4A939F" xlink:to="loc_us-gaap_PaymentsOfDividendsCommonStock_B3A789E83E027F59705017C2BB4B6961" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_C32DA9632EC9B9B8D72217C2BB4BB101" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_C280F5E710E1535DB84417C2BB4A939F" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_C32DA9632EC9B9B8D72217C2BB4BB101" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_53E3BEAB6F2A9E1B7C5C17C2BB4B7710" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B7217310CD3D59ACBD0217C2BB3FE1F7" xlink:to="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_53E3BEAB6F2A9E1B7C5C17C2BB4B7710" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_7B02B04D42794046A40D17C2BB4BD8B4" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B7217310CD3D59ACBD0217C2BB3FE1F7" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_7B02B04D42794046A40D17C2BB4BD8B4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_AEBEE8DA444CE828232517C2BB4C5D4A" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B7217310CD3D59ACBD0217C2BB3FE1F7" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_AEBEE8DA444CE828232517C2BB4C5D4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract_38DE4BC4200E5C9A333217C2BB4C9F52" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B7217310CD3D59ACBD0217C2BB3FE1F7" xlink:to="loc_us-gaap_SupplementalCashFlowInformationAbstract_38DE4BC4200E5C9A333217C2BB4C9F52" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeTaxesPaid" xlink:label="loc_us-gaap_IncomeTaxesPaid_C0D75E4E1CB7BE4900E617C2BB4CDEED" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_38DE4BC4200E5C9A333217C2BB4C9F52" xlink:to="loc_us-gaap_IncomeTaxesPaid_C0D75E4E1CB7BE4900E617C2BB4CDEED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InterestPaid" xlink:label="loc_us-gaap_InterestPaid_2C3FEBFE8C4A5CCC33C117C2BB4CCEAB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_38DE4BC4200E5C9A333217C2BB4C9F52" xlink:to="loc_us-gaap_InterestPaid_2C3FEBFE8C4A5CCC33C117C2BB4CCEAB" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_C123E0724F9B5B508EDCFD15F6B452DB" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_F484B773E4FB89DE7BE3FD15F6B49CDD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_C123E0724F9B5B508EDCFD15F6B452DB" xlink:to="loc_us-gaap_StatementTable_F484B773E4FB89DE7BE3FD15F6B49CDD" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_1F14D82ED0F22002BED8FD15F6B4CE92" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_F484B773E4FB89DE7BE3FD15F6B49CDD" xlink:to="loc_us-gaap_StatementScenarioAxis_1F14D82ED0F22002BED8FD15F6B4CE92" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_34FE8A5047335C0BCA5FFD15F6B48C7F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_1F14D82ED0F22002BED8FD15F6B4CE92" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_34FE8A5047335C0BCA5FFD15F6B48C7F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_34FE8A5047335C0BCA5FFD15F6B48C7F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_1F14D82ED0F22002BED8FD15F6B4CE92" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_34FE8A5047335C0BCA5FFD15F6B48C7F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_A87C157F872898ACAFA3FD15F6B41D4D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C123E0724F9B5B508EDCFD15F6B452DB" xlink:to="loc_us-gaap_NetIncomeLoss_A87C157F872898ACAFA3FD15F6B41D4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent_012F4E8F98CC90340748FD15F6B53B45" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C123E0724F9B5B508EDCFD15F6B452DB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent_012F4E8F98CC90340748FD15F6B53B45" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax_24B6BC78A0C160757EDCFD15F6B570C1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C123E0724F9B5B508EDCFD15F6B452DB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax_24B6BC78A0C160757EDCFD15F6B570C1" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_OtherComprehensiveIncomeLossAmortizationPensionAndOtherPostretirementBenefitPlansNetPriorServiceCostAndNetGainLossRecognizedInNetPeriodicBenefitCostBeforeTax" xlink:label="loc_ayi_OtherComprehensiveIncomeLossAmortizationPensionAndOtherPostretirementBenefitPlansNetPriorServiceCostAndNetGainLossRecognizedInNetPeriodicBenefitCostBeforeTax_001CB197B50977062D0AFD15F6B5105D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C123E0724F9B5B508EDCFD15F6B452DB" xlink:to="loc_ayi_OtherComprehensiveIncomeLossAmortizationPensionAndOtherPostretirementBenefitPlansNetPriorServiceCostAndNetGainLossRecognizedInNetPeriodicBenefitCostBeforeTax_001CB197B50977062D0AFD15F6B5105D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent_67E3175A77928E28596BFD15F6B56749" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C123E0724F9B5B508EDCFD15F6B452DB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent_67E3175A77928E28596BFD15F6B56749" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent_9E140E16C7AAAFEF9F85FD15F6B597E1" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C123E0724F9B5B508EDCFD15F6B452DB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent_9E140E16C7AAAFEF9F85FD15F6B597E1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_BF8A500D04C179FC408EFD15F6B53498" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C123E0724F9B5B508EDCFD15F6B452DB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_BF8A500D04C179FC408EFD15F6B53498" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_18899D4279E4D108C5C5FD15F6B55E17" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C123E0724F9B5B508EDCFD15F6B452DB" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_18899D4279E4D108C5C5FD15F6B55E17" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_840ACF08F8D44BA9A889FD15F6B5C1C8" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C123E0724F9B5B508EDCFD15F6B452DB" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_840ACF08F8D44BA9A889FD15F6B5C1C8" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/ConsolidatedStatementsOfIncome" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_8E3CF4A0A34542A7C79115A451A76F5A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_1F799BF59223129CD9E615A451A74303" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_8E3CF4A0A34542A7C79115A451A76F5A" xlink:to="loc_us-gaap_StatementTable_1F799BF59223129CD9E615A451A74303" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_98550557F4A55EF65BAF15A451A7A710" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_1F799BF59223129CD9E615A451A74303" xlink:to="loc_dei_LegalEntityAxis_98550557F4A55EF65BAF15A451A7A710" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_DD6609FFDDA24A36F8A215A451A7E435_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_98550557F4A55EF65BAF15A451A7A710" xlink:to="loc_dei_EntityDomain_DD6609FFDDA24A36F8A215A451A7E435_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_DD6609FFDDA24A36F8A215A451A7E435" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_98550557F4A55EF65BAF15A451A7A710" xlink:to="loc_dei_EntityDomain_DD6609FFDDA24A36F8A215A451A7E435" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SalesRevenueGoodsNet" xlink:label="loc_us-gaap_SalesRevenueGoodsNet_A3045BF9C4FCC7D1940A15A451A771E2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8E3CF4A0A34542A7C79115A451A76F5A" xlink:to="loc_us-gaap_SalesRevenueGoodsNet_A3045BF9C4FCC7D1940A15A451A771E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:label="loc_us-gaap_CostOfGoodsSold_6A4FD6F2393CBEB70BD615A451A7384D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8E3CF4A0A34542A7C79115A451A76F5A" xlink:to="loc_us-gaap_CostOfGoodsSold_6A4FD6F2393CBEB70BD615A451A7384D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_28856E64769C7DE49BFD15A451A7F98E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8E3CF4A0A34542A7C79115A451A76F5A" xlink:to="loc_us-gaap_GrossProfit_28856E64769C7DE49BFD15A451A7F98E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_1368D0ED1BA7140F677515A451A77031" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8E3CF4A0A34542A7C79115A451A76F5A" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_1368D0ED1BA7140F677515A451A77031" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestructuringCharges" xlink:label="loc_us-gaap_RestructuringCharges_9D01502DE3DA2AC5CD9D15A451A77A6B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8E3CF4A0A34542A7C79115A451A76F5A" xlink:to="loc_us-gaap_RestructuringCharges_9D01502DE3DA2AC5CD9D15A451A77A6B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_63A21BE3244C6E0DCA3115A451AC3395" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8E3CF4A0A34542A7C79115A451A76F5A" xlink:to="loc_us-gaap_OperatingIncomeLoss_63A21BE3244C6E0DCA3115A451AC3395" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NonoperatingIncomeExpenseAbstract" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract_77E1F1FA5BD19559552915A451AD91BA" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8E3CF4A0A34542A7C79115A451A76F5A" xlink:to="loc_us-gaap_NonoperatingIncomeExpenseAbstract_77E1F1FA5BD19559552915A451AD91BA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InterestRevenueExpenseNet" xlink:label="loc_us-gaap_InterestRevenueExpenseNet_178E575438EB9A5B9A8615A451AD361E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_77E1F1FA5BD19559552915A451AD91BA" xlink:to="loc_us-gaap_InterestRevenueExpenseNet_178E575438EB9A5B9A8615A451AD361E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_4C8C1DCD64373191A2EF15A451AD9461" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_77E1F1FA5BD19559552915A451AD91BA" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_4C8C1DCD64373191A2EF15A451AD9461" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_OtherNonoperatingExpenses" xlink:label="loc_ayi_OtherNonoperatingExpenses_0D6CAD286B99D1891C5F15A451AD0BBA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_77E1F1FA5BD19559552915A451AD91BA" xlink:to="loc_ayi_OtherNonoperatingExpenses_0D6CAD286B99D1891C5F15A451AD0BBA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_D55D8686A0EEEF0B35AE15A451ADD4EE" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8E3CF4A0A34542A7C79115A451A76F5A" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_D55D8686A0EEEF0B35AE15A451ADD4EE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_51F8AA0335B2DCF296EF15A451AD5DA6" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8E3CF4A0A34542A7C79115A451A76F5A" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_51F8AA0335B2DCF296EF15A451AD5DA6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_FFF3B00FD2EFCDA0432415A451AD4096" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8E3CF4A0A34542A7C79115A451A76F5A" xlink:to="loc_us-gaap_NetIncomeLoss_FFF3B00FD2EFCDA0432415A451AD4096" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="loc_us-gaap_EarningsPerShareAbstract_59926A05400A1F84E1D515A451ADB22C" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8E3CF4A0A34542A7C79115A451A76F5A" xlink:to="loc_us-gaap_EarningsPerShareAbstract_59926A05400A1F84E1D515A451ADB22C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_B8F5D9597FAA0CA603E415A451ADE6F7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_59926A05400A1F84E1D515A451ADB22C" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_B8F5D9597FAA0CA603E415A451ADE6F7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_E1F4DC0028C3FF317B6415A451AE98AD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_59926A05400A1F84E1D515A451ADB22C" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_E1F4DC0028C3FF317B6415A451AE98AD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_1FF0F35421BC4B050E0115A451AE4031" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_59926A05400A1F84E1D515A451ADB22C" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_1FF0F35421BC4B050E0115A451AE4031" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_0832AE6149BCF3282BC515A451AEDBE0" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_59926A05400A1F84E1D515A451ADB22C" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_0832AE6149BCF3282BC515A451AEDBE0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockDividendsPerShareDeclared" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_3D07595ACBAC39EB190F15A451AE803D" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8E3CF4A0A34542A7C79115A451A76F5A" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_3D07595ACBAC39EB190F15A451AE803D" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/DebtDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_F1FE489A5E0FC996511E17CC1CE2296B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_63E9FAA6D346AC0912C017CC1CE0C9B9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F1FE489A5E0FC996511E17CC1CE2296B" xlink:to="loc_us-gaap_DebtInstrumentTable_63E9FAA6D346AC0912C017CC1CE0C9B9" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_951934EFA696F4D52EDC17CC1CE026BC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_63E9FAA6D346AC0912C017CC1CE0C9B9" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_951934EFA696F4D52EDC17CC1CE026BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_482316EFB235B761660E17CC1CE177E9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_951934EFA696F4D52EDC17CC1CE026BC" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_482316EFB235B761660E17CC1CE177E9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_482316EFB235B761660E17CC1CE177E9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_951934EFA696F4D52EDC17CC1CE026BC" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_482316EFB235B761660E17CC1CE177E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="loc_us-gaap_LineOfCreditMember_9C2FC90222DEFD7A38D517CC1CE169CC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_482316EFB235B761660E17CC1CE177E9" xlink:to="loc_us-gaap_LineOfCreditMember_9C2FC90222DEFD7A38D517CC1CE169CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_2E24AD55A35D309B634017CC1CE1EF18" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_482316EFB235B761660E17CC1CE177E9" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_2E24AD55A35D309B634017CC1CE1EF18" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_TaxExemptIndustrialRevenueBondMember" xlink:label="loc_ayi_TaxExemptIndustrialRevenueBondMember_BE4154DAF1C4B80B399C17CC1CE1E924" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_482316EFB235B761660E17CC1CE177E9" xlink:to="loc_ayi_TaxExemptIndustrialRevenueBondMember_BE4154DAF1C4B80B399C17CC1CE1E924" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_1E3EEAAA7AE65329177D17CC1CE1A5EE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_63E9FAA6D346AC0912C017CC1CE0C9B9" xlink:to="loc_us-gaap_DebtInstrumentAxis_1E3EEAAA7AE65329177D17CC1CE1A5EE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_9FF25F46E54EC5BD097117CC1CE1DDE7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_1E3EEAAA7AE65329177D17CC1CE1A5EE" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_9FF25F46E54EC5BD097117CC1CE1DDE7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_9FF25F46E54EC5BD097117CC1CE1DDE7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_1E3EEAAA7AE65329177D17CC1CE1A5EE" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_9FF25F46E54EC5BD097117CC1CE1DDE7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_74A7386ACC093FD4A11717CC1CE1FEAB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_9FF25F46E54EC5BD097117CC1CE1DDE7" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_74A7386ACC093FD4A11717CC1CE1FEAB" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_PriorFacilityMember" xlink:label="loc_ayi_PriorFacilityMember_E3D5DF0F18B311ACDEC117CC1CE16113" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_9FF25F46E54EC5BD097117CC1CE1DDE7" xlink:to="loc_ayi_PriorFacilityMember_E3D5DF0F18B311ACDEC117CC1CE16113" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_69CE837D69D70394B4BB17CC1CE106F6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_63E9FAA6D346AC0912C017CC1CE0C9B9" xlink:to="loc_us-gaap_RangeAxis_69CE837D69D70394B4BB17CC1CE106F6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_3B8034F98D3AAC5149CF17CC1CE15926_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_69CE837D69D70394B4BB17CC1CE106F6" xlink:to="loc_us-gaap_RangeMember_3B8034F98D3AAC5149CF17CC1CE15926_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_3B8034F98D3AAC5149CF17CC1CE15926" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_69CE837D69D70394B4BB17CC1CE106F6" xlink:to="loc_us-gaap_RangeMember_3B8034F98D3AAC5149CF17CC1CE15926" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_DA74379CDC3FC56EE4DA17CC1CE113F5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_3B8034F98D3AAC5149CF17CC1CE15926" xlink:to="loc_us-gaap_MinimumMember_DA74379CDC3FC56EE4DA17CC1CE113F5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_DC1401C3F100A7A2AAEF17CC1CE139AE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_3B8034F98D3AAC5149CF17CC1CE15926" xlink:to="loc_us-gaap_MaximumMember_DC1401C3F100A7A2AAEF17CC1CE139AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityAbstract" xlink:label="loc_us-gaap_LineOfCreditFacilityAbstract_63B2ED356362C418F1B517CC1CE2EB2F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F1FE489A5E0FC996511E17CC1CE2296B" xlink:to="loc_us-gaap_LineOfCreditFacilityAbstract_63B2ED356362C418F1B517CC1CE2EB2F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_541589D051D52267E5EE17CC1CE2F9FD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_63B2ED356362C418F1B517CC1CE2EB2F" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_541589D051D52267E5EE17CC1CE2F9FD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WriteOffOfDeferredDebtIssuanceCost" xlink:label="loc_us-gaap_WriteOffOfDeferredDebtIssuanceCost_7A5B869D8AF26602BD9817CC1CE2F09A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_63B2ED356362C418F1B517CC1CE2EB2F" xlink:to="loc_us-gaap_WriteOffOfDeferredDebtIssuanceCost_7A5B869D8AF26602BD9817CC1CE2F09A" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_LineOfCreditFacilityLeverageRatioIndebtednessToEbitda" xlink:label="loc_ayi_LineOfCreditFacilityLeverageRatioIndebtednessToEbitda_E9454317E4E0C2036D8517CC1CE2E2DC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_63B2ED356362C418F1B517CC1CE2EB2F" xlink:to="loc_ayi_LineOfCreditFacilityLeverageRatioIndebtednessToEbitda_E9454317E4E0C2036D8517CC1CE2E2DC" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_LineOfCreditFacilityInterestCoverageRatio" xlink:label="loc_ayi_LineOfCreditFacilityInterestCoverageRatio_75D7698A6D5CB9DFC95E17CC1CE21CCE" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_63B2ED356362C418F1B517CC1CE2EB2F" xlink:to="loc_ayi_LineOfCreditFacilityInterestCoverageRatio_75D7698A6D5CB9DFC95E17CC1CE21CCE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_A0078FC7246CA274D9D517CC1CE29AE2" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_63B2ED356362C418F1B517CC1CE2EB2F" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_A0078FC7246CA274D9D517CC1CE29AE2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_F3F7AA421C7DF522103A17CC1CE2A1A7" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_63B2ED356362C418F1B517CC1CE2EB2F" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_F3F7AA421C7DF522103A17CC1CE2A1A7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate_335546B3EC29362E4F0317CC1CE270AA" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_63B2ED356362C418F1B517CC1CE2EB2F" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate_335546B3EC29362E4F0317CC1CE270AA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_84B3A73038746A69C7BD17CC1CE253DD" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_63B2ED356362C418F1B517CC1CE2EB2F" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_84B3A73038746A69C7BD17CC1CE253DD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentsAbstract" xlink:label="loc_us-gaap_DebtInstrumentsAbstract_9F825126129848A845B117CC1CE3A7C8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F1FE489A5E0FC996511E17CC1CE2296B" xlink:to="loc_us-gaap_DebtInstrumentsAbstract_9F825126129848A845B117CC1CE3A7C8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_A5017E598963A46ACE6A17CC1CE3B2B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentsAbstract_9F825126129848A845B117CC1CE3A7C8" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_A5017E598963A46ACE6A17CC1CE3B2B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_7FCE42E06097BAEAD67317CC1CE3361F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentsAbstract_9F825126129848A845B117CC1CE3A7C8" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_7FCE42E06097BAEAD67317CC1CE3361F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_15526332C95F63FFA83017CC1CE30B0E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentsAbstract_9F825126129848A845B117CC1CE3A7C8" xlink:to="loc_us-gaap_LongTermDebt_15526332C95F63FFA83017CC1CE30B0E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InterestRevenueOrExpenseNetAbstract" xlink:label="loc_us-gaap_InterestRevenueOrExpenseNetAbstract_B5A5E8B1AC3D1FEC5E0C17CC1CE3801E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F1FE489A5E0FC996511E17CC1CE2296B" xlink:to="loc_us-gaap_InterestRevenueOrExpenseNetAbstract_B5A5E8B1AC3D1FEC5E0C17CC1CE3801E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_FEC6AF86E1312C30596F17CC1CE34976" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestRevenueOrExpenseNetAbstract_B5A5E8B1AC3D1FEC5E0C17CC1CE3801E" xlink:to="loc_us-gaap_InterestExpense_FEC6AF86E1312C30596F17CC1CE34976" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="loc_us-gaap_InvestmentIncomeInterest_0349F008B26D85EBA6F217CC1CE3F7B3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestRevenueOrExpenseNetAbstract_B5A5E8B1AC3D1FEC5E0C17CC1CE3801E" xlink:to="loc_us-gaap_InvestmentIncomeInterest_0349F008B26D85EBA6F217CC1CE3F7B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InterestRevenueExpenseNet" xlink:label="loc_us-gaap_InterestRevenueExpenseNet_07B44B41F045BD00B90417CC1CE31F76" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestRevenueOrExpenseNetAbstract_B5A5E8B1AC3D1FEC5E0C17CC1CE3801E" xlink:to="loc_us-gaap_InterestRevenueExpenseNet_07B44B41F045BD00B90417CC1CE31F76" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract_F863B8521190B80C44BD17CC1CE3D4EC" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F1FE489A5E0FC996511E17CC1CE2296B" xlink:to="loc_us-gaap_SupplementalCashFlowInformationAbstract_F863B8521190B80C44BD17CC1CE3D4EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InterestPaid" xlink:label="loc_us-gaap_InterestPaid_4F1F7B5049EF30D9615617CC1CE3763A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_F863B8521190B80C44BD17CC1CE3D4EC" xlink:to="loc_us-gaap_InterestPaid_4F1F7B5049EF30D9615617CC1CE3763A" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/EarningsPerShareDetails" xlink:type="extended">
    <link:loc xlink:href="ayi-20121130.xsd#ayi_EarningsPerShareBasicAndDilutedLineItems" xlink:label="loc_ayi_EarningsPerShareBasicAndDilutedLineItems_6C1E6C65FCC7C8A6DD92FCD97353AB88" xlink:type="locator" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_ScheduleOfEarningsPerShareBasicAndDilutedTable" xlink:label="loc_ayi_ScheduleOfEarningsPerShareBasicAndDilutedTable_04D7D75B8585DC3D2B73FCD9734DD8B6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ayi_EarningsPerShareBasicAndDilutedLineItems_6C1E6C65FCC7C8A6DD92FCD97353AB88" xlink:to="loc_ayi_ScheduleOfEarningsPerShareBasicAndDilutedTable_04D7D75B8585DC3D2B73FCD9734DD8B6" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_BC5AD9FE79E8F8109366FCD973521CF0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ayi_ScheduleOfEarningsPerShareBasicAndDilutedTable_04D7D75B8585DC3D2B73FCD9734DD8B6" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_BC5AD9FE79E8F8109366FCD973521CF0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_266851F1E2C8E5FD7AB5FCD973539F06_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_BC5AD9FE79E8F8109366FCD973521CF0" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_266851F1E2C8E5FD7AB5FCD973539F06_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_266851F1E2C8E5FD7AB5FCD973539F06" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_BC5AD9FE79E8F8109366FCD973521CF0" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_266851F1E2C8E5FD7AB5FCD973539F06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="loc_us-gaap_StockOptionsMember_F17FE67DD37E21354F66FCD97353589E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_266851F1E2C8E5FD7AB5FCD973539F06" xlink:to="loc_us-gaap_StockOptionsMember_F17FE67DD37E21354F66FCD97353589E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_B012599C9B1AA20951F0FCD973536AFC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ayi_EarningsPerShareBasicAndDilutedLineItems_6C1E6C65FCC7C8A6DD92FCD97353AB88" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_B012599C9B1AA20951F0FCD973536AFC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EarningsPerShareBasicAbstract" xlink:label="loc_us-gaap_EarningsPerShareBasicAbstract_32110A7C581F41A549BFFCD97353C791" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ayi_EarningsPerShareBasicAndDilutedLineItems_6C1E6C65FCC7C8A6DD92FCD97353AB88" xlink:to="loc_us-gaap_EarningsPerShareBasicAbstract_32110A7C581F41A549BFFCD97353C791" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_9E22F685E56D38E1F283FCD97353494F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_32110A7C581F41A549BFFCD97353C791" xlink:to="loc_us-gaap_NetIncomeLoss_9E22F685E56D38E1F283FCD97353494F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarnings" xlink:label="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarnings_F701C8403EB5589D380DFCD973535638" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_32110A7C581F41A549BFFCD97353C791" xlink:to="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarnings_F701C8403EB5589D380DFCD973535638" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_03B9E333C961C34FD86CFCD97354A66E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_32110A7C581F41A549BFFCD97353C791" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_03B9E333C961C34FD86CFCD97354A66E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_4DC1D028F00EC842C02BFCD97354F53C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_32110A7C581F41A549BFFCD97353C791" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_4DC1D028F00EC842C02BFCD97354F53C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_F6E748C9E351E6F53DF0FCD973542BA7" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_32110A7C581F41A549BFFCD97353C791" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_F6E748C9E351E6F53DF0FCD973542BA7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EarningsPerShareDilutedAbstract" xlink:label="loc_us-gaap_EarningsPerShareDilutedAbstract_9CFEED8B538117BED1E8FCD9735448F4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ayi_EarningsPerShareBasicAndDilutedLineItems_6C1E6C65FCC7C8A6DD92FCD97353AB88" xlink:to="loc_us-gaap_EarningsPerShareDilutedAbstract_9CFEED8B538117BED1E8FCD9735448F4" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_ParticipatingSecuritiesDistributedAndUndistributedEarningsDilute" xlink:label="loc_ayi_ParticipatingSecuritiesDistributedAndUndistributedEarningsDilute_C82D2D846FEDB4721EA0FCD973548EC5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_9CFEED8B538117BED1E8FCD9735448F4" xlink:to="loc_ayi_ParticipatingSecuritiesDistributedAndUndistributedEarningsDilute_C82D2D846FEDB4721EA0FCD973548EC5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_3F823C48313300CB252DFCD973545137" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_9CFEED8B538117BED1E8FCD9735448F4" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_3F823C48313300CB252DFCD973545137" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" xlink:label="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_CB1A9E4ABC509C75029FFCD97355556D" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_9CFEED8B538117BED1E8FCD9735448F4" xlink:to="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_CB1A9E4ABC509C75029FFCD97355556D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_271A8F077302FB2FC123FCD973554C6F" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_9CFEED8B538117BED1E8FCD9735448F4" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_271A8F077302FB2FC123FCD973554C6F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_1B5A53F1A139B6A0444EFCD973559549" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_9CFEED8B538117BED1E8FCD9735448F4" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_1B5A53F1A139B6A0444EFCD973559549" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/FairValueMeasurementsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_A3BFDEA862CC8010B3D4BDDA051A1091" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_A3E5998D7B7679BC39D9BDDA0517A2CA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_A3BFDEA862CC8010B3D4BDDA051A1091" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_A3E5998D7B7679BC39D9BDDA0517A2CA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_579A20E34CF70DA3D665BDDA05172865" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_A3E5998D7B7679BC39D9BDDA0517A2CA" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_579A20E34CF70DA3D665BDDA05172865" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_D7F7EC505182CDE16B5BBDDA0517415F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_579A20E34CF70DA3D665BDDA05172865" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_D7F7EC505182CDE16B5BBDDA0517415F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_D7F7EC505182CDE16B5BBDDA0517415F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_579A20E34CF70DA3D665BDDA05172865" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_D7F7EC505182CDE16B5BBDDA0517415F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_4E9FF2EFA0EC0A4B888FBDDA0518BA70" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_D7F7EC505182CDE16B5BBDDA0517415F" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_4E9FF2EFA0EC0A4B888FBDDA0518BA70" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_376597EB37CA1423E43BBDDA05180197" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_A3E5998D7B7679BC39D9BDDA0517A2CA" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_376597EB37CA1423E43BBDDA05180197" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_70F59A0D62E1CEAE2269BDDA0518213E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_376597EB37CA1423E43BBDDA05180197" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_70F59A0D62E1CEAE2269BDDA0518213E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_70F59A0D62E1CEAE2269BDDA0518213E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_376597EB37CA1423E43BBDDA05180197" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_70F59A0D62E1CEAE2269BDDA0518213E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_61AAC9B5EDA4A5C8A981BDDA05189B92" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_70F59A0D62E1CEAE2269BDDA0518213E" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_61AAC9B5EDA4A5C8A981BDDA05189B92" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_1170EECEF13589CAE365BDDA0518EC8F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_70F59A0D62E1CEAE2269BDDA0518213E" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_1170EECEF13589CAE365BDDA0518EC8F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InvestmentTypeAxis" xlink:label="loc_us-gaap_InvestmentTypeAxis_A5B873082A349AE1B471BDDA0518B268" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_A3E5998D7B7679BC39D9BDDA0517A2CA" xlink:to="loc_us-gaap_InvestmentTypeAxis_A5B873082A349AE1B471BDDA0518B268" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_209428665D10F1E1D14CBDDA051957B6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_A5B873082A349AE1B471BDDA0518B268" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_209428665D10F1E1D14CBDDA051957B6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_209428665D10F1E1D14CBDDA051957B6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_A5B873082A349AE1B471BDDA0518B268" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_209428665D10F1E1D14CBDDA051957B6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShortTermInvestmentsMember" xlink:label="loc_us-gaap_ShortTermInvestmentsMember_9F8B9DCF456210A96C86BDDA05190E39" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_209428665D10F1E1D14CBDDA051957B6" xlink:to="loc_us-gaap_ShortTermInvestmentsMember_9F8B9DCF456210A96C86BDDA05190E39" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherLongTermInvestmentsMember" xlink:label="loc_us-gaap_OtherLongTermInvestmentsMember_16F6AAC05293CC50051CBDDA051933BB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_209428665D10F1E1D14CBDDA051957B6" xlink:to="loc_us-gaap_OtherLongTermInvestmentsMember_16F6AAC05293CC50051CBDDA051933BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_CC3FFC15578B3C8D6C5DBDDA0519AD81" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_A3E5998D7B7679BC39D9BDDA0517A2CA" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_CC3FFC15578B3C8D6C5DBDDA0519AD81" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_089E050B90C7EC5096CDBDDA0519656A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_CC3FFC15578B3C8D6C5DBDDA0519AD81" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_089E050B90C7EC5096CDBDDA0519656A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_089E050B90C7EC5096CDBDDA0519656A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_CC3FFC15578B3C8D6C5DBDDA0519AD81" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_089E050B90C7EC5096CDBDDA0519656A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_E6ED0E83A82E6B74E1CCBDDA0519D995" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_089E050B90C7EC5096CDBDDA0519656A" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_E6ED0E83A82E6B74E1CCBDDA0519D995" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_TaxExemptIndustrialRevenueBondMember" xlink:label="loc_ayi_TaxExemptIndustrialRevenueBondMember_EE769F54152687C54136BDDA0519B1FB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_089E050B90C7EC5096CDBDDA0519656A" xlink:to="loc_ayi_TaxExemptIndustrialRevenueBondMember_EE769F54152687C54136BDDA0519B1FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis_B061B2D269A711C72272BDDA0519B30C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_A3E5998D7B7679BC39D9BDDA0517A2CA" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis_B061B2D269A711C72272BDDA0519B30C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_4E03C15FB8D70CF7E4F7BDDA05195F5F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis_B061B2D269A711C72272BDDA0519B30C" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_4E03C15FB8D70CF7E4F7BDDA05195F5F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_4E03C15FB8D70CF7E4F7BDDA05195F5F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis_B061B2D269A711C72272BDDA0519B30C" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_4E03C15FB8D70CF7E4F7BDDA05195F5F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_79596E12E6BF4D0D5F4EBDDA051A1E15" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_4E03C15FB8D70CF7E4F7BDDA05195F5F" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_79596E12E6BF4D0D5F4EBDDA051A1E15" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_108D25A407CDC0618DB0BDDA051AE6AE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_4E03C15FB8D70CF7E4F7BDDA05195F5F" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_108D25A407CDC0618DB0BDDA051AE6AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_9A6CDC216CB09018603DBDDA051AE48F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_A3BFDEA862CC8010B3D4BDDA051A1091" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_9A6CDC216CB09018603DBDDA051AE48F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_9145727F078387AC31DABDDA051ACDF7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_9A6CDC216CB09018603DBDDA051AE48F" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_9145727F078387AC31DABDDA051ACDF7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InvestmentsFairValueDisclosure" xlink:label="loc_us-gaap_InvestmentsFairValueDisclosure_B25D5501D8AC09DC310FBDDA051A3AF0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_9A6CDC216CB09018603DBDDA051AE48F" xlink:to="loc_us-gaap_InvestmentsFairValueDisclosure_B25D5501D8AC09DC310FBDDA051A3AF0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_E03E4D7D38181E7E68D4BDDA051FA17D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_A3BFDEA862CC8010B3D4BDDA051A1091" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_E03E4D7D38181E7E68D4BDDA051FA17D" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_DeferredCompensationPlanFairValueDisclosureCurrentMaturities" xlink:label="loc_ayi_DeferredCompensationPlanFairValueDisclosureCurrentMaturities_645A2983DE30A72F9E85BDDA051FF4AE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_E03E4D7D38181E7E68D4BDDA051FA17D" xlink:to="loc_ayi_DeferredCompensationPlanFairValueDisclosureCurrentMaturities_645A2983DE30A72F9E85BDDA051FF4AE" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_DeferredCompensationPlanFairValueDisclosureExcludingCurrentMaturities" xlink:label="loc_ayi_DeferredCompensationPlanFairValueDisclosureExcludingCurrentMaturities_5972E8349DAC05685EBEBDDA051F13FA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_E03E4D7D38181E7E68D4BDDA051FA17D" xlink:to="loc_ayi_DeferredCompensationPlanFairValueDisclosureExcludingCurrentMaturities_5972E8349DAC05685EBEBDDA051F13FA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_37B8C2D17FE1C317F881BDDA051F3B5B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_A3BFDEA862CC8010B3D4BDDA051A1091" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_37B8C2D17FE1C317F881BDDA051F3B5B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebtFairValue" xlink:label="loc_us-gaap_LongTermDebtFairValue_CDDB946DF7AB3D7FE10FBDDA051F8912" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_37B8C2D17FE1C317F881BDDA051F3B5B" xlink:to="loc_us-gaap_LongTermDebtFairValue_CDDB946DF7AB3D7FE10FBDDA051F8912" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/PensionAndProfitSharingPlansDetails" xlink:type="extended">
    <link:loc xlink:href="ayi-20121130.xsd#ayi_EmployeeRetirementBenefitsLineItems" xlink:label="loc_ayi_EmployeeRetirementBenefitsLineItems_030A6BB4BE16EC44DF4C17CC1CC21E19" xlink:type="locator" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_EmployeeRetirementBenefitsTable" xlink:label="loc_ayi_EmployeeRetirementBenefitsTable_AABE81C2C9CF1F69F2E817CC1CC17895" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ayi_EmployeeRetirementBenefitsLineItems_030A6BB4BE16EC44DF4C17CC1CC21E19" xlink:to="loc_ayi_EmployeeRetirementBenefitsTable_AABE81C2C9CF1F69F2E817CC1CC17895" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_60EC722DFAC69EA6CD4E17CC1CC210E8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ayi_EmployeeRetirementBenefitsTable_AABE81C2C9CF1F69F2E817CC1CC17895" xlink:to="loc_us-gaap_StatementScenarioAxis_60EC722DFAC69EA6CD4E17CC1CC210E8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_626717940C7E7CDDDA9417CC1CC2E7B7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_60EC722DFAC69EA6CD4E17CC1CC210E8" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_626717940C7E7CDDDA9417CC1CC2E7B7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_626717940C7E7CDDDA9417CC1CC2E7B7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_60EC722DFAC69EA6CD4E17CC1CC210E8" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_626717940C7E7CDDDA9417CC1CC2E7B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScenarioForecastMember" xlink:label="loc_us-gaap_ScenarioForecastMember_85B04575472C63C9D37717CC1CC25735" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScenarioUnspecifiedDomain_626717940C7E7CDDDA9417CC1CC2E7B7" xlink:to="loc_us-gaap_ScenarioForecastMember_85B04575472C63C9D37717CC1CC25735" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_IncreaseDecreaseInPensionExpense" xlink:label="loc_ayi_IncreaseDecreaseInPensionExpense_28A7B820487F4D3DC63717CC1CC22FE7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ayi_EmployeeRetirementBenefitsLineItems_030A6BB4BE16EC44DF4C17CC1CC21E19" xlink:to="loc_ayi_IncreaseDecreaseInPensionExpense_28A7B820487F4D3DC63717CC1CC22FE7" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SpecialChargeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestructuringCostAndReserveLineItems" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_C32EE8C1006498324AC617CC1CB4C646" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_0E3977EB71A61395F77517CC1CB21184" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_C32EE8C1006498324AC617CC1CB4C646" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_0E3977EB71A61395F77517CC1CB21184" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_96610D2E3A4BEC055A8417CC1CB21DDF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_0E3977EB71A61395F77517CC1CB21184" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_96610D2E3A4BEC055A8417CC1CB21DDF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_FAF72E89FE4A780A3DE617CC1CB21288_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_96610D2E3A4BEC055A8417CC1CB21DDF" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_FAF72E89FE4A780A3DE617CC1CB21288_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_FAF72E89FE4A780A3DE617CC1CB21288" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_96610D2E3A4BEC055A8417CC1CB21DDF" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_FAF72E89FE4A780A3DE617CC1CB21288" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestructuringChargesMember" xlink:label="loc_us-gaap_RestructuringChargesMember_61C2D7C83FDE51654B0E17CC1CB24B13" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_FAF72E89FE4A780A3DE617CC1CB21288" xlink:to="loc_us-gaap_RestructuringChargesMember_61C2D7C83FDE51654B0E17CC1CB24B13" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CostOfSalesMember" xlink:label="loc_us-gaap_CostOfSalesMember_A612C546A2658B90779217CC1CB23C44" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_FAF72E89FE4A780A3DE617CC1CB21288" xlink:to="loc_us-gaap_CostOfSalesMember_A612C546A2658B90779217CC1CB23C44" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_RestructuringActivityByActionsYearAxis" xlink:label="loc_ayi_RestructuringActivityByActionsYearAxis_481CCA3132805902E28C17CC1CB20C03" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_0E3977EB71A61395F77517CC1CB21184" xlink:to="loc_ayi_RestructuringActivityByActionsYearAxis_481CCA3132805902E28C17CC1CB20C03" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_RestructuringActivityByActionsYearDomain" xlink:label="loc_ayi_RestructuringActivityByActionsYearDomain_0FB50430F044CD7B5ECB17CC1CB274FE_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ayi_RestructuringActivityByActionsYearAxis_481CCA3132805902E28C17CC1CB20C03" xlink:to="loc_ayi_RestructuringActivityByActionsYearDomain_0FB50430F044CD7B5ECB17CC1CB274FE_default" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_RestructuringActivityByActionsYearDomain" xlink:label="loc_ayi_RestructuringActivityByActionsYearDomain_0FB50430F044CD7B5ECB17CC1CB274FE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ayi_RestructuringActivityByActionsYearAxis_481CCA3132805902E28C17CC1CB20C03" xlink:to="loc_ayi_RestructuringActivityByActionsYearDomain_0FB50430F044CD7B5ECB17CC1CB274FE" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_Fiscal2008To2010ActionsRestructuringActivityMember" xlink:label="loc_ayi_Fiscal2008To2010ActionsRestructuringActivityMember_89C69E0DD96B8B38977D17CC1CB27E2C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ayi_RestructuringActivityByActionsYearDomain_0FB50430F044CD7B5ECB17CC1CB274FE" xlink:to="loc_ayi_Fiscal2008To2010ActionsRestructuringActivityMember_89C69E0DD96B8B38977D17CC1CB27E2C" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_Fiscal2012ActionsRestructuringActivityMember" xlink:label="loc_ayi_Fiscal2012ActionsRestructuringActivityMember_81594BA8ABB483DFBA3917CC1CB2D8CE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ayi_RestructuringActivityByActionsYearDomain_0FB50430F044CD7B5ECB17CC1CB274FE" xlink:to="loc_ayi_Fiscal2012ActionsRestructuringActivityMember_81594BA8ABB483DFBA3917CC1CB2D8CE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_E59D68CF547FEC56A97217CC1CB39A87" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_0E3977EB71A61395F77517CC1CB21184" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_E59D68CF547FEC56A97217CC1CB39A87" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_ADDB898EF0203C0CEEA417CC1CB3CBA1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_E59D68CF547FEC56A97217CC1CB39A87" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_ADDB898EF0203C0CEEA417CC1CB3CBA1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_ADDB898EF0203C0CEEA417CC1CB3CBA1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_E59D68CF547FEC56A97217CC1CB39A87" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_ADDB898EF0203C0CEEA417CC1CB3CBA1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SalesRevenueGoodsNetMember" xlink:label="loc_us-gaap_SalesRevenueGoodsNetMember_48ED17014AFCE08CB50117CC1CB331F7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_ADDB898EF0203C0CEEA417CC1CB3CBA1" xlink:to="loc_us-gaap_SalesRevenueGoodsNetMember_48ED17014AFCE08CB50117CC1CB331F7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_DBA5F483F6876FE7796417CC1CB3AA54" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_0E3977EB71A61395F77517CC1CB21184" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_DBA5F483F6876FE7796417CC1CB3AA54" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_ABAE37AA49BB8F423D1D17CC1CB3296C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_DBA5F483F6876FE7796417CC1CB3AA54" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_ABAE37AA49BB8F423D1D17CC1CB3296C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_ABAE37AA49BB8F423D1D17CC1CB3296C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_DBA5F483F6876FE7796417CC1CB3AA54" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_ABAE37AA49BB8F423D1D17CC1CB3296C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProductConcentrationRiskMember" xlink:label="loc_us-gaap_ProductConcentrationRiskMember_E4A71806986442852A5C17CC1CB3FE05" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_ABAE37AA49BB8F423D1D17CC1CB3296C" xlink:to="loc_us-gaap_ProductConcentrationRiskMember_E4A71806986442852A5C17CC1CB3FE05" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_4F7B3BDAD16C1FD429D117CC1CB319DD" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_0E3977EB71A61395F77517CC1CB21184" xlink:to="loc_us-gaap_RangeAxis_4F7B3BDAD16C1FD429D117CC1CB319DD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_0613EAE8B79BF7BECA5F17CC1CB352E3_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_4F7B3BDAD16C1FD429D117CC1CB319DD" xlink:to="loc_us-gaap_RangeMember_0613EAE8B79BF7BECA5F17CC1CB352E3_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_0613EAE8B79BF7BECA5F17CC1CB352E3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_4F7B3BDAD16C1FD429D117CC1CB319DD" xlink:to="loc_us-gaap_RangeMember_0613EAE8B79BF7BECA5F17CC1CB352E3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_A3F9588018DBEFB7EA0C17CC1CB391F3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_0613EAE8B79BF7BECA5F17CC1CB352E3" xlink:to="loc_us-gaap_MaximumMember_A3F9588018DBEFB7EA0C17CC1CB391F3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestructuringCostAndReserveAxis" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_504186B793C1EAF1B62117CC1CB4213D" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_0E3977EB71A61395F77517CC1CB21184" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_504186B793C1EAF1B62117CC1CB4213D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_78F41FFA7747B1B820ED17CC1CB4B2BA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_504186B793C1EAF1B62117CC1CB4213D" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_78F41FFA7747B1B820ED17CC1CB4B2BA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_78F41FFA7747B1B820ED17CC1CB4B2BA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_504186B793C1EAF1B62117CC1CB4213D" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_78F41FFA7747B1B820ED17CC1CB4B2BA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeSeveranceMember" xlink:label="loc_us-gaap_EmployeeSeveranceMember_7973FA28F9BDC577FCEA17CC1CB44135" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_78F41FFA7747B1B820ED17CC1CB4B2BA" xlink:to="loc_us-gaap_EmployeeSeveranceMember_7973FA28F9BDC577FCEA17CC1CB44135" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FacilityClosingMember" xlink:label="loc_us-gaap_FacilityClosingMember_34CCA07D556CE878A44E17CC1CB432D5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_78F41FFA7747B1B820ED17CC1CB4B2BA" xlink:to="loc_us-gaap_FacilityClosingMember_34CCA07D556CE878A44E17CC1CB432D5" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_EmployeeSeveranceAndBenefitsMember" xlink:label="loc_ayi_EmployeeSeveranceAndBenefitsMember_B8B4572CF2D19B2C90B517CC1CB4F0C0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FacilityClosingMember_34CCA07D556CE878A44E17CC1CB432D5" xlink:to="loc_ayi_EmployeeSeveranceAndBenefitsMember_B8B4572CF2D19B2C90B517CC1CB4F0C0" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_ProductionTransferMember" xlink:label="loc_ayi_ProductionTransferMember_7BD2DD41BCF6FC93EA5217CC1CB40476" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FacilityClosingMember_34CCA07D556CE878A44E17CC1CB432D5" xlink:to="loc_ayi_ProductionTransferMember_7BD2DD41BCF6FC93EA5217CC1CB40476" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherRestructuringMember" xlink:label="loc_us-gaap_OtherRestructuringMember_AA1FF53AB7F23BD4367217CC1CB416D6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FacilityClosingMember_34CCA07D556CE878A44E17CC1CB432D5" xlink:to="loc_us-gaap_OtherRestructuringMember_AA1FF53AB7F23BD4367217CC1CB416D6" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_NonCashAssetImpairmentsMember" xlink:label="loc_ayi_NonCashAssetImpairmentsMember_3D978FE7D757601B122C17CC1CB4AAE8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_78F41FFA7747B1B820ED17CC1CB4B2BA" xlink:to="loc_ayi_NonCashAssetImpairmentsMember_3D978FE7D757601B122C17CC1CB4AAE8" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_ManufacturingInefficienciesMember" xlink:label="loc_ayi_ManufacturingInefficienciesMember_F64E2BC973D73C1E91DE17CC1CB4447E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_78F41FFA7747B1B820ED17CC1CB4B2BA" xlink:to="loc_ayi_ManufacturingInefficienciesMember_F64E2BC973D73C1E91DE17CC1CB4447E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OneTimeTerminationBenefitsMember" xlink:label="loc_us-gaap_OneTimeTerminationBenefitsMember_E85428A7E0D43630A4AB17CC1CB4D49A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_78F41FFA7747B1B820ED17CC1CB4B2BA" xlink:to="loc_us-gaap_OneTimeTerminationBenefitsMember_E85428A7E0D43630A4AB17CC1CB4D49A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestructuringAndRelatedCostIncurredCost" xlink:label="loc_us-gaap_RestructuringAndRelatedCostIncurredCost_68223C54CFD6094F9D6E17CC1CB4D475" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_C32EE8C1006498324AC617CC1CB4C646" xlink:to="loc_us-gaap_RestructuringAndRelatedCostIncurredCost_68223C54CFD6094F9D6E17CC1CB4D475" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_61DB051B783CFFEA765C17CC1CB4ACDF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_C32EE8C1006498324AC617CC1CB4C646" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_61DB051B783CFFEA765C17CC1CB4ACDF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestructuringReserveRollForward" xlink:label="loc_us-gaap_RestructuringReserveRollForward_00DB174A3E0D1034DA7617CC1CB4F70B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_C32EE8C1006498324AC617CC1CB4C646" xlink:to="loc_us-gaap_RestructuringReserveRollForward_00DB174A3E0D1034DA7617CC1CB4F70B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestructuringReserve" xlink:label="loc_us-gaap_RestructuringReserve_49F4588E164E62C352F517CC1CB5AB91" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_00DB174A3E0D1034DA7617CC1CB4F70B" xlink:to="loc_us-gaap_RestructuringReserve_49F4588E164E62C352F517CC1CB5AB91" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestructuringCharges" xlink:label="loc_us-gaap_RestructuringCharges_500DC1D92098FE2883EE17CC1CB5DC0F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_00DB174A3E0D1034DA7617CC1CB4F70B" xlink:to="loc_us-gaap_RestructuringCharges_500DC1D92098FE2883EE17CC1CB5DC0F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestructuringReserveSettledWithCash" xlink:label="loc_us-gaap_RestructuringReserveSettledWithCash_09982CD95471BD8D001117CC1CB562F0" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_00DB174A3E0D1034DA7617CC1CB4F70B" xlink:to="loc_us-gaap_RestructuringReserveSettledWithCash_09982CD95471BD8D001117CC1CB562F0" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsBalanceSheetsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CondensedFinancialStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_9667521F59D01FD1881117CB7526A46B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfCondensedFinancialStatementsTable" xlink:label="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_3C81DB1EFAA941678DFC17CB7525BFEC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_9667521F59D01FD1881117CB7526A46B" xlink:to="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_3C81DB1EFAA941678DFC17CB7525BFEC" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_A18AA0CDBA43FFD6E1A117CB7525D99D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_3C81DB1EFAA941678DFC17CB7525BFEC" xlink:to="loc_dei_LegalEntityAxis_A18AA0CDBA43FFD6E1A117CB7525D99D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_D5E0A421FE5762BC8A6F17CB7526E4D6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_A18AA0CDBA43FFD6E1A117CB7525D99D" xlink:to="loc_dei_EntityDomain_D5E0A421FE5762BC8A6F17CB7526E4D6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_D5E0A421FE5762BC8A6F17CB7526E4D6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_A18AA0CDBA43FFD6E1A117CB7525D99D" xlink:to="loc_dei_EntityDomain_D5E0A421FE5762BC8A6F17CB7526E4D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ParentCompanyMember" xlink:label="loc_us-gaap_ParentCompanyMember_1A7D04A7D218D3242ADA17CB7526FED9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_D5E0A421FE5762BC8A6F17CB7526E4D6" xlink:to="loc_us-gaap_ParentCompanyMember_1A7D04A7D218D3242ADA17CB7526FED9" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_IssuerSubsidiariesMember" xlink:label="loc_ayi_IssuerSubsidiariesMember_A63B7BB0E6B24647C8ED17CB7526D5F9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_D5E0A421FE5762BC8A6F17CB7526E4D6" xlink:to="loc_ayi_IssuerSubsidiariesMember_A63B7BB0E6B24647C8ED17CB7526D5F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_93FF0399A23E1D50EA9517CB75267C9C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_D5E0A421FE5762BC8A6F17CB7526E4D6" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_93FF0399A23E1D50EA9517CB75267C9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_31D7FB1A8B83C504B77517CB75265B54" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_D5E0A421FE5762BC8A6F17CB7526E4D6" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_31D7FB1A8B83C504B77517CB75265B54" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_33863A76DB4D6E29634317CB75263984" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_D5E0A421FE5762BC8A6F17CB7526E4D6" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_33863A76DB4D6E29634317CB75263984" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_05D626AD1BDB76333D9817CB75268529" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_9667521F59D01FD1881117CB7526A46B" xlink:to="loc_us-gaap_AssetsAbstract_05D626AD1BDB76333D9817CB75268529" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract_60F03482A8C54A13A5C917CB75279CAF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_05D626AD1BDB76333D9817CB75268529" xlink:to="loc_us-gaap_AssetsCurrentAbstract_60F03482A8C54A13A5C917CB75279CAF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_2D79BB6B4D5203280B5D17CB7527C015" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_60F03482A8C54A13A5C917CB75279CAF" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_2D79BB6B4D5203280B5D17CB7527C015" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_5B27EC01BB22681C946417CB75279A38" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_60F03482A8C54A13A5C917CB75279CAF" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_5B27EC01BB22681C946417CB75279A38" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_7DBACB9419BCFCCF4CD017CB75271660" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_60F03482A8C54A13A5C917CB75279CAF" xlink:to="loc_us-gaap_InventoryNet_7DBACB9419BCFCCF4CD017CB75271660" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherAssetsCurrent" xlink:label="loc_us-gaap_OtherAssetsCurrent_269F494BEBF60764662417CB75278100" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_60F03482A8C54A13A5C917CB75279CAF" xlink:to="loc_us-gaap_OtherAssetsCurrent_269F494BEBF60764662417CB75278100" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_F35AECB23B1202FF40BD17CB7527DBEA" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_60F03482A8C54A13A5C917CB75279CAF" xlink:to="loc_us-gaap_AssetsCurrent_F35AECB23B1202FF40BD17CB7527DBEA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_06AD79D944DA4CA031EF17CB752742C1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_05D626AD1BDB76333D9817CB75268529" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_06AD79D944DA4CA031EF17CB752742C1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_FD221FCACA4BA64F49B017CB7527128D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_05D626AD1BDB76333D9817CB75268529" xlink:to="loc_us-gaap_Goodwill_FD221FCACA4BA64F49B017CB7527128D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_DFA1A71FDA70E06F189A17CB7527464C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_05D626AD1BDB76333D9817CB75268529" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_DFA1A71FDA70E06F189A17CB7527464C" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_OtherLongTermAndDeferredTaxAssetsNoncurrent" xlink:label="loc_ayi_OtherLongTermAndDeferredTaxAssetsNoncurrent_A8F61C63C3E7C2CC8A8017CB752729B0" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_05D626AD1BDB76333D9817CB75268529" xlink:to="loc_ayi_OtherLongTermAndDeferredTaxAssetsNoncurrent_A8F61C63C3E7C2CC8A8017CB752729B0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:label="loc_us-gaap_EquityMethodInvestments_FB12156E7C7E581BFEF217CB75270C9C" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_05D626AD1BDB76333D9817CB75268529" xlink:to="loc_us-gaap_EquityMethodInvestments_FB12156E7C7E581BFEF217CB75270C9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_11AD4337F3AF7CC16CA317CB7528BA06" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_05D626AD1BDB76333D9817CB75268529" xlink:to="loc_us-gaap_Assets_11AD4337F3AF7CC16CA317CB7528BA06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_BD905968A0E0A48AC55C17CB7528757A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_9667521F59D01FD1881117CB7526A46B" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_BD905968A0E0A48AC55C17CB7528757A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_A6863AA6B44102BA7AA517CB7528FC22" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_BD905968A0E0A48AC55C17CB7528757A" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_A6863AA6B44102BA7AA517CB7528FC22" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_1F3E272BE6EF3545DC6D17CB752891F8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_A6863AA6B44102BA7AA517CB7528FC22" xlink:to="loc_us-gaap_AccountsPayableCurrent_1F3E272BE6EF3545DC6D17CB752891F8" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_IntercompanyPayableReceivable" xlink:label="loc_ayi_IntercompanyPayableReceivable_AAE23E4C41A69727E1A617CB7528AA3B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_A6863AA6B44102BA7AA517CB7528FC22" xlink:to="loc_ayi_IntercompanyPayableReceivable_AAE23E4C41A69727E1A617CB7528AA3B" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_OtherAccruedAndEmployeeRelatedLiabilitesCurrent" xlink:label="loc_ayi_OtherAccruedAndEmployeeRelatedLiabilitesCurrent_A23C94776936CD6FB3F517CB752828AE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_A6863AA6B44102BA7AA517CB7528FC22" xlink:to="loc_ayi_OtherAccruedAndEmployeeRelatedLiabilitesCurrent_A23C94776936CD6FB3F517CB752828AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_19FDDAC79C98AE9198CE17CB75289DBF" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_A6863AA6B44102BA7AA517CB7528FC22" xlink:to="loc_us-gaap_LiabilitiesCurrent_19FDDAC79C98AE9198CE17CB75289DBF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_12FEE937EBC38B21EFB217CB752827EF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_BD905968A0E0A48AC55C17CB7528757A" xlink:to="loc_us-gaap_LongTermDebt_12FEE937EBC38B21EFB217CB752827EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DeferredTaxLiabilitiesNoncurrent" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesNoncurrent_9744C3256332ED3723E017CB752866F8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_BD905968A0E0A48AC55C17CB7528757A" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesNoncurrent_9744C3256332ED3723E017CB752866F8" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_OtherLongTermLiabilitiesAccruedPensionAndSelfInsuranceReservesNoncurrent" xlink:label="loc_ayi_OtherLongTermLiabilitiesAccruedPensionAndSelfInsuranceReservesNoncurrent_9F991EC0B85AB8440F4817CB752810F9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_BD905968A0E0A48AC55C17CB7528757A" xlink:to="loc_ayi_OtherLongTermLiabilitiesAccruedPensionAndSelfInsuranceReservesNoncurrent_9F991EC0B85AB8440F4817CB752810F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_49EFBAE661C65E538C5817CB75284A7D" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_BD905968A0E0A48AC55C17CB7528757A" xlink:to="loc_us-gaap_StockholdersEquity_49EFBAE661C65E538C5817CB75284A7D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_7A8C04359FC57B33780C17CB752982A6" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_BD905968A0E0A48AC55C17CB7528757A" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_7A8C04359FC57B33780C17CB752982A6" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsCashFlowsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CondensedFinancialStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_B2B0C46E093A13994A0117BF8C5C920A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfCondensedFinancialStatementsTable" xlink:label="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_B8477CAF3A1E3FE1159D17BF8C5B6314" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_B2B0C46E093A13994A0117BF8C5C920A" xlink:to="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_B8477CAF3A1E3FE1159D17BF8C5B6314" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_955931B6D3A867B363F717BF8C5BE13D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_B8477CAF3A1E3FE1159D17BF8C5B6314" xlink:to="loc_dei_LegalEntityAxis_955931B6D3A867B363F717BF8C5BE13D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_15FA19C78506BF41F69517BF8C5B7CBD_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_955931B6D3A867B363F717BF8C5BE13D" xlink:to="loc_dei_EntityDomain_15FA19C78506BF41F69517BF8C5B7CBD_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_15FA19C78506BF41F69517BF8C5B7CBD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_955931B6D3A867B363F717BF8C5BE13D" xlink:to="loc_dei_EntityDomain_15FA19C78506BF41F69517BF8C5B7CBD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ParentCompanyMember" xlink:label="loc_us-gaap_ParentCompanyMember_4DA781AFB0F79A44C7BB17BF8C5BBBA3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_15FA19C78506BF41F69517BF8C5B7CBD" xlink:to="loc_us-gaap_ParentCompanyMember_4DA781AFB0F79A44C7BB17BF8C5BBBA3" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_IssuerSubsidiariesMember" xlink:label="loc_ayi_IssuerSubsidiariesMember_666A509216CF38475F1B17BF8C5B9DC2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_15FA19C78506BF41F69517BF8C5B7CBD" xlink:to="loc_ayi_IssuerSubsidiariesMember_666A509216CF38475F1B17BF8C5B9DC2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_0B81C298C37F3CDA420617BF8C5B7DA8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_15FA19C78506BF41F69517BF8C5B7CBD" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_0B81C298C37F3CDA420617BF8C5B7DA8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_71EE675A50A177812F0C17BF8C5B2344" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_15FA19C78506BF41F69517BF8C5B7CBD" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_71EE675A50A177812F0C17BF8C5B2344" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_015CF57A1F6A1EE7C01917BF8C5CC4A2" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_15FA19C78506BF41F69517BF8C5B7CBD" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_015CF57A1F6A1EE7C01917BF8C5CC4A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_9516B4670058A33DCB2417BF8C5C9A8F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_B2B0C46E093A13994A0117BF8C5C920A" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_9516B4670058A33DCB2417BF8C5C9A8F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_E1A5E064A420A6743DE017BF8C5CB937" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_B2B0C46E093A13994A0117BF8C5C920A" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_E1A5E064A420A6743DE017BF8C5CB937" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_74E90A1E9DAE2DBC226A17BF8C5CA42A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_E1A5E064A420A6743DE017BF8C5CB937" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_74E90A1E9DAE2DBC226A17BF8C5CA42A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates" xlink:label="loc_us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates_4781DDBA7DA339FB916B17BF8C5CA078" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_E1A5E064A420A6743DE017BF8C5CB937" xlink:to="loc_us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates_4781DDBA7DA339FB916B17BF8C5CA078" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_B7BCFC13DE117406F5EE17BF8C5C8620" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_E1A5E064A420A6743DE017BF8C5CB937" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_B7BCFC13DE117406F5EE17BF8C5C8620" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_7D28D2FD7F452DF6C45B17BF8C5C2928" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_E1A5E064A420A6743DE017BF8C5CB937" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_7D28D2FD7F452DF6C45B17BF8C5C2928" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D1B351452803352DE62B17BF8C5C030B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_B2B0C46E093A13994A0117BF8C5C920A" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D1B351452803352DE62B17BF8C5C030B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_CC859CCCC8AD5504CA2117BF8C5D08AD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D1B351452803352DE62B17BF8C5C030B" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_CC859CCCC8AD5504CA2117BF8C5D08AD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_B908FBAF8A438E73E2C217BF8C5D6FD3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D1B351452803352DE62B17BF8C5C030B" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_B908FBAF8A438E73E2C217BF8C5D6FD3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:label="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_8EE3D47B7AF26BCE0EB117BF8C5D36B9" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D1B351452803352DE62B17BF8C5C030B" xlink:to="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_8EE3D47B7AF26BCE0EB117BF8C5D36B9" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_IntercompanyDividends" xlink:label="loc_ayi_IntercompanyDividends_8C5F44AED88C3898EDB717BF8C5DEF76" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D1B351452803352DE62B17BF8C5C030B" xlink:to="loc_ayi_IntercompanyDividends_8C5F44AED88C3898EDB717BF8C5DEF76" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_IntercompanyCapital" xlink:label="loc_ayi_IntercompanyCapital_0C696CA8ABBD4553E4BF17BF8C5D1AA6" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D1B351452803352DE62B17BF8C5C030B" xlink:to="loc_ayi_IntercompanyCapital_0C696CA8ABBD4553E4BF17BF8C5D1AA6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsOfDividendsCommonStock" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock_BC8717BEA1395399A60717BF8C5D606E" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D1B351452803352DE62B17BF8C5C030B" xlink:to="loc_us-gaap_PaymentsOfDividendsCommonStock_BC8717BEA1395399A60717BF8C5D606E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_7BD7E173C08EE9BB444B17BF8C5DBB8D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_D1B351452803352DE62B17BF8C5C030B" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_7BD7E173C08EE9BB444B17BF8C5DBB8D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents" xlink:label="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_471D826873DCAB99284F17BF8C5DE602" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_B2B0C46E093A13994A0117BF8C5C920A" xlink:to="loc_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_471D826873DCAB99284F17BF8C5DE602" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_6EE3E4110B2EBDB6537017BF8C5DD3A7" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_B2B0C46E093A13994A0117BF8C5C920A" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_6EE3E4110B2EBDB6537017BF8C5DD3A7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_050AC3A28B951C0BEC1517BF8C5DE966" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_B2B0C46E093A13994A0117BF8C5C920A" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_050AC3A28B951C0BEC1517BF8C5DE966" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsIncomeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CondensedFinancialStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfCondensedFinancialStatementsTable" xlink:label="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_23FA97F54C35F0AA1A8517C8640C8CC9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:to="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_23FA97F54C35F0AA1A8517C8640C8CC9" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_0297F9ABE7AFF983D74117C8640CD8A6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_23FA97F54C35F0AA1A8517C8640C8CC9" xlink:to="loc_dei_LegalEntityAxis_0297F9ABE7AFF983D74117C8640CD8A6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_91B3E5C9F75071F49F5E17C8640CD2F0_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_0297F9ABE7AFF983D74117C8640CD8A6" xlink:to="loc_dei_EntityDomain_91B3E5C9F75071F49F5E17C8640CD2F0_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_91B3E5C9F75071F49F5E17C8640CD2F0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_0297F9ABE7AFF983D74117C8640CD8A6" xlink:to="loc_dei_EntityDomain_91B3E5C9F75071F49F5E17C8640CD2F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ParentCompanyMember" xlink:label="loc_us-gaap_ParentCompanyMember_106F402CC53DB0E936A217C8640C9D07" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_91B3E5C9F75071F49F5E17C8640CD2F0" xlink:to="loc_us-gaap_ParentCompanyMember_106F402CC53DB0E936A217C8640C9D07" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_IssuerSubsidiariesMember" xlink:label="loc_ayi_IssuerSubsidiariesMember_1B6298DB0BD8E02D09A117C8640DAB67" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_91B3E5C9F75071F49F5E17C8640CD2F0" xlink:to="loc_ayi_IssuerSubsidiariesMember_1B6298DB0BD8E02D09A117C8640DAB67" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_6D3980D174E417C0AF6817C8640DFDFF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_91B3E5C9F75071F49F5E17C8640CD2F0" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_6D3980D174E417C0AF6817C8640DFDFF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_6E2FCE8A71D9FD76934117C8640D8C56" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_91B3E5C9F75071F49F5E17C8640CD2F0" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_6E2FCE8A71D9FD76934117C8640D8C56" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_C7B0BD3959BE05E204F917C8640E0D8F" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_91B3E5C9F75071F49F5E17C8640CD2F0" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_C7B0BD3959BE05E204F917C8640E0D8F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SalesRevenueGoodsNetAbstract" xlink:label="loc_us-gaap_SalesRevenueGoodsNetAbstract_CA13EBD8A428309E008417C8640E4A3C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:to="loc_us-gaap_SalesRevenueGoodsNetAbstract_CA13EBD8A428309E008417C8640E4A3C" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_SalesRevenueGoodsExternal" xlink:label="loc_ayi_SalesRevenueGoodsExternal_7B41F2C5DD66B865E2D317C8640E0DCA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesRevenueGoodsNetAbstract_CA13EBD8A428309E008417C8640E4A3C" xlink:to="loc_ayi_SalesRevenueGoodsExternal_7B41F2C5DD66B865E2D317C8640E0DCA" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_SalesRevenueGoodsIntercompany" xlink:label="loc_ayi_SalesRevenueGoodsIntercompany_7D9EC6286C4E0A461D0B17C8640E6B80" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesRevenueGoodsNetAbstract_CA13EBD8A428309E008417C8640E4A3C" xlink:to="loc_ayi_SalesRevenueGoodsIntercompany_7D9EC6286C4E0A461D0B17C8640E6B80" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SalesRevenueGoodsNet" xlink:label="loc_us-gaap_SalesRevenueGoodsNet_9826456117F839DBC83A17C8640FF0BE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesRevenueGoodsNetAbstract_CA13EBD8A428309E008417C8640E4A3C" xlink:to="loc_us-gaap_SalesRevenueGoodsNet_9826456117F839DBC83A17C8640FF0BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CostOfGoodsSold" xlink:label="loc_us-gaap_CostOfGoodsSold_2A69E38FA91E8825CEBA17C8640F2900" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:to="loc_us-gaap_CostOfGoodsSold_2A69E38FA91E8825CEBA17C8640F2900" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_859D42BD2DA3BF1B16B817C8640F745B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:to="loc_us-gaap_GrossProfit_859D42BD2DA3BF1B16B817C8640F745B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_530D173991E84AF3788E17C8640F44BE" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_530D173991E84AF3788E17C8640F44BE" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_IntercompanyCharges" xlink:label="loc_ayi_IntercompanyCharges_4CCA14B4C66BCA342E0D17C8640F2176" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:to="loc_ayi_IntercompanyCharges_4CCA14B4C66BCA342E0D17C8640F2176" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestructuringCharges" xlink:label="loc_us-gaap_RestructuringCharges_FD5E6DEFF6F237298AE317C8640F9384" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:to="loc_us-gaap_RestructuringCharges_FD5E6DEFF6F237298AE317C8640F9384" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_7731C6B3A2A96867188D17C86410EFF5" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:to="loc_us-gaap_OperatingIncomeLoss_7731C6B3A2A96867188D17C86410EFF5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InterestRevenueExpenseNet" xlink:label="loc_us-gaap_InterestRevenueExpenseNet_ACA3FAC9E3DC4A8F680717C864108E85" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:to="loc_us-gaap_InterestRevenueExpenseNet_ACA3FAC9E3DC4A8F680717C864108E85" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TemporaryEquityInterestInSubsidiaryEarnings" xlink:label="loc_us-gaap_TemporaryEquityInterestInSubsidiaryEarnings_E550D0175FBAEEC0FC5917C864107E21" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:to="loc_us-gaap_TemporaryEquityInterestInSubsidiaryEarnings_E550D0175FBAEEC0FC5917C864107E21" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_C5A9C83A53BCC5B5F50517C8641064B7" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_C5A9C83A53BCC5B5F50517C8641064B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_B4C9F9AD6888F56D9F2D17C86410629A" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_B4C9F9AD6888F56D9F2D17C86410629A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_A5F6B9B062BFA75C6EE317C8641074E3" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_A5F6B9B062BFA75C6EE317C8641074E3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_CD57CA7D7A0E88E04F0A17C86410BBC3" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_85A5BEAE7BAE04CEC34417C8640EF9B3" xlink:to="loc_us-gaap_NetIncomeLoss_CD57CA7D7A0E88E04F0A17C86410BBC3" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.acuitybrands.com/role/SupplementalGuarantorCondensedConsolidatingFinancialStatementsOtherComprehensiveIncomeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CondensedFinancialStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_C1F7E6FB6C74C5DC121B17CC1CA2CD42" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfCondensedFinancialStatementsTable" xlink:label="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_72F37A1151266B626D0D17CC1CA1F886" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_C1F7E6FB6C74C5DC121B17CC1CA2CD42" xlink:to="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_72F37A1151266B626D0D17CC1CA1F886" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_8276ED0DC8DE0671982017CC1CA14482" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_72F37A1151266B626D0D17CC1CA1F886" xlink:to="loc_dei_LegalEntityAxis_8276ED0DC8DE0671982017CC1CA14482" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_22F64287D03DBF8EDD4C17CC1CA1971F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_8276ED0DC8DE0671982017CC1CA14482" xlink:to="loc_dei_EntityDomain_22F64287D03DBF8EDD4C17CC1CA1971F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_22F64287D03DBF8EDD4C17CC1CA1971F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_8276ED0DC8DE0671982017CC1CA14482" xlink:to="loc_dei_EntityDomain_22F64287D03DBF8EDD4C17CC1CA1971F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_D0EE52C324C5CC101A2D17CC1CA1FDC1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_22F64287D03DBF8EDD4C17CC1CA1971F" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_D0EE52C324C5CC101A2D17CC1CA1FDC1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_783339E9E85E61A28BBA17CC1CA1D300" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_22F64287D03DBF8EDD4C17CC1CA1971F" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_783339E9E85E61A28BBA17CC1CA1D300" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_C87089B7FEA00B5FE5DF17CC1CA12481" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_22F64287D03DBF8EDD4C17CC1CA1971F" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_C87089B7FEA00B5FE5DF17CC1CA12481" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_IssuerSubsidiariesMember" xlink:label="loc_ayi_IssuerSubsidiariesMember_E88864C2B53913DC2AF017CC1CA27EE6" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_22F64287D03DBF8EDD4C17CC1CA1971F" xlink:to="loc_ayi_IssuerSubsidiariesMember_E88864C2B53913DC2AF017CC1CA27EE6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ParentCompanyMember" xlink:label="loc_us-gaap_ParentCompanyMember_8B27F91BCB053059E2F017CC1CA21B30" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_22F64287D03DBF8EDD4C17CC1CA1971F" xlink:to="loc_us-gaap_ParentCompanyMember_8B27F91BCB053059E2F017CC1CA21B30" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_7AE6B5DF5A1A49D5FA7817CC1CA2934F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_C1F7E6FB6C74C5DC121B17CC1CA2CD42" xlink:to="loc_us-gaap_NetIncomeLoss_7AE6B5DF5A1A49D5FA7817CC1CA2934F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent_4D3964B6FF2215B9806F17CC1CA25A4F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_C1F7E6FB6C74C5DC121B17CC1CA2CD42" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent_4D3964B6FF2215B9806F17CC1CA25A4F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax_A5C92619CD737432710117CC1CA2A1DF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_C1F7E6FB6C74C5DC121B17CC1CA2CD42" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax_A5C92619CD737432710117CC1CA2A1DF" xlink:type="arc" />
    <link:loc xlink:href="ayi-20121130.xsd#ayi_OtherComprehensiveIncomeLossAmortizationPensionAndOtherPostretirementBenefitPlansNetPriorServiceCostAndNetGainLossRecognizedInNetPeriodicBenefitCostBeforeTax" xlink:label="loc_ayi_OtherComprehensiveIncomeLossAmortizationPensionAndOtherPostretirementBenefitPlansNetPriorServiceCostAndNetGainLossRecognizedInNetPeriodicBenefitCostBeforeTax_56F223E24CA8D8D9BE8517CC1CA2DB5C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_C1F7E6FB6C74C5DC121B17CC1CA2CD42" xlink:to="loc_ayi_OtherComprehensiveIncomeLossAmortizationPensionAndOtherPostretirementBenefitPlansNetPriorServiceCostAndNetGainLossRecognizedInNetPeriodicBenefitCostBeforeTax_56F223E24CA8D8D9BE8517CC1CA2DB5C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent_F897B6C867C6526E344C17CC1CA222F9" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_C1F7E6FB6C74C5DC121B17CC1CA2CD42" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent_F897B6C867C6526E344C17CC1CA222F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent_E9929708DEAD39D5660B17CC1CA264FB" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_C1F7E6FB6C74C5DC121B17CC1CA2CD42" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent_E9929708DEAD39D5660B17CC1CA264FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_18F13AAE8A014579842B17CC1CA3383F" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_C1F7E6FB6C74C5DC121B17CC1CA2CD42" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_18F13AAE8A014579842B17CC1CA3383F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_4C1E7A743A4A48A2A6F217CC1CA3488E" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_C1F7E6FB6C74C5DC121B17CC1CA2CD42" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_4C1E7A743A4A48A2A6F217CC1CA3488E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_8E2E859C1682BB65DEA117CC1CA32C59" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_C1F7E6FB6C74C5DC121B17CC1CA2CD42" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_8E2E859C1682BB65DEA117CC1CA32C59" xlink:type="arc" />
  </link:definitionLink>
</link:linkbase>
