<?xml version="1.0" encoding="UTF-8" ?>
<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:xbrldi="http://xbrl.org/2006/xbrldi"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xbrli="http://www.xbrl.org/2003/instance"
xmlns:xlink="http://www.w3.org/1999/xlink">
<link:roleRef
roleURI="http://xbrl.sec.gov/rr/role/Series"
xlink:type="simple"
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#SeriesOnly"/>
<link:roleRef
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#ClassOnly"
xlink:type="simple"
roleURI="http://xbrl.sec.gov/rr/role/Class"/>
<link:roleRef
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#PerformanceMeasureOnly"
xlink:type="simple"
roleURI="http://xbrl.sec.gov/rr/role/PerformanceMeasure"/>
<link:roleRef
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#ProspectusOnly"
xlink:type="simple"
roleURI="http://xbrl.sec.gov/rr/role/Prospectus"/>
<link:roleRef
xlink:href="convertible-20140326.xsd#Supplement"
xlink:type="simple"
roleURI="http://vanguard/role/Supplement"/>
<link:roleRef
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#RiskReturn"
xlink:type="simple"
roleURI="http://xbrl.sec.gov/rr/role/RiskReturn"/>
<link:roleRef
roleURI="http://xbrl.sec.gov/rr/role/RiskReturnDetailData"
xlink:type="simple"
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#RiskReturnDetailData"/>
<link:roleRef
roleURI="http://xbrl.sec.gov/rr/role/PerformanceTableData"
xlink:type="simple"
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#PerformanceTableData"/>
<link:roleRef
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#ShareholderFeesData"
xlink:type="simple"
roleURI="http://xbrl.sec.gov/rr/role/ShareholderFeesData"/>
<link:roleRef
roleURI="http://xbrl.sec.gov/rr/role/OperatingExpensesData"
xlink:type="simple"
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#OperatingExpensesData"/>
<link:roleRef
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#BarChartData"
xlink:type="simple"
roleURI="http://xbrl.sec.gov/rr/role/BarChartData"/>
<link:arcroleRef
arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member"
xlink:type="simple"
xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
<link:arcroleRef
arcroleURI="http://xbrl.org/int/dim/arcrole/all"
xlink:type="simple"
xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
<link:arcroleRef
arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension"
xlink:type="simple"
xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
<link:arcroleRef
arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain"
xlink:type="simple"
xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
<link:definitionLink
xlink:type="extended"
xlink:role="http://xbrl.sec.gov/rr/role/Series">
<link:loc
xlink:type="locator"
xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain"
xlink:label="EntityDomain"/>
<link:loc
xlink:type="locator"
xlink:href="convertible-20140326.xsd#vanguard_S000002837Member"
xlink:label="S000002837Member"/>
<link:definitionArc
xlink:from="EntityDomain"
xlink:type="arc"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member"
order="1.0"
xlink:to="S000002837Member"/></link:definitionLink>
<link:definitionLink
xlink:role="http://xbrl.sec.gov/rr/role/Class"
xlink:type="extended">
<link:loc
xlink:type="locator"
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#rr_ProspectusShareClassAxis"
xlink:label="ProspectusShareClassAxis"/>
<link:loc
xlink:label="C000007767Member"
xlink:href="convertible-20140326.xsd#vanguard_C000007767Member"
xlink:type="locator"/>
<link:definitionArc
xlink:from="ProspectusShareClassAxis"
xlink:type="arc"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain"
order="2.0"
xlink:to="C000007767Member"/></link:definitionLink>
<link:definitionLink
xlink:role="http://xbrl.sec.gov/rr/role/PerformanceMeasure"
xlink:type="extended">
<link:loc
xlink:type="locator"
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#rr_PerformanceMeasureAxis"
xlink:label="PerformanceMeasureAxis"/>
<link:loc
xlink:type="locator"
xlink:href="convertible-20140326.xsd#vanguard_BasedOnMarketMember"
xlink:label="BasedOnMarketMember"/>
<link:loc
xlink:label="PerformanceMeasureDomain"
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#rr_PerformanceMeasureDomain"
xlink:type="locator"/>
<link:loc
xlink:type="locator"
xlink:href="convertible-20140326.xsd#vanguard_ConvertibleSecuritiesFundsAverageMember"
xlink:label="ConvertibleSecuritiesFundsAverageMember"/>
<link:definitionArc
xlink:to="ConvertibleSecuritiesFundsAverageMember"
order="3.0"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain"
xlink:type="arc"
xlink:from="PerformanceMeasureAxis"/>
<link:loc
xlink:type="locator"
xlink:href="convertible-20140326.xsd#vanguard_BankofAmericaMerrillLynchAllUSConvertiblesMember"
xlink:label="BankofAmericaMerrillLynchAllUSConvertiblesMember"/>
<link:definitionArc
xlink:to="BankofAmericaMerrillLynchAllUSConvertiblesMember"
order="4.0"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain"
xlink:type="arc"
xlink:from="PerformanceMeasureAxis"/>
<link:loc
xlink:type="locator"
xlink:href="convertible-20140326.xsd#vanguard_ConvertiblesCompositeIndexMember"
xlink:label="ConvertiblesCompositeIndexMember"/>
<link:definitionArc
xlink:to="ConvertiblesCompositeIndexMember"
order="5.0"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain"
xlink:type="arc"
xlink:from="PerformanceMeasureAxis"/>
<link:definitionArc
xlink:to="BasedOnMarketMember"
order="6.0"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member"
xlink:type="arc"
xlink:from="PerformanceMeasureDomain"/></link:definitionLink>
<link:definitionLink
xlink:role="http://xbrl.sec.gov/rr/role/Prospectus"
xlink:type="extended">
<link:loc
xlink:type="locator"
xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_DocumentDomain"
xlink:label="DocumentDomain"/>
<link:definitionArc
xlink:from="DocumentDomain"
xlink:type="arc"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member"
order="7.0"
xlink:to="ParticipantMember"/>
<link:loc
xlink:label="ParticipantMember"
xlink:href="convertible-20140326.xsd#vanguard_ParticipantMember"
xlink:type="locator"/>
<link:definitionArc
xlink:from="DocumentDomain"
xlink:type="arc"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member"
order="8.0"
xlink:to="RetailMember"/>
<link:loc
xlink:label="RetailMember"
xlink:href="convertible-20140326.xsd#vanguard_RetailMember"
xlink:type="locator"/></link:definitionLink>
<link:definitionLink
xlink:role="http://vanguard/role/Supplement"
xlink:type="extended">
<link:loc
xlink:type="locator"
xlink:href="convertible-20140326.xsd#vanguard_SupplementTextBlock"
xlink:label="SupplementTextBlock"/>
<link:loc
xlink:label="LegalEntityAxis"
xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis"
xlink:type="locator"/>
<link:loc
xlink:label="DocumentInformationDocumentAxis"
xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_DocumentInformationDocumentAxis"
xlink:type="locator"/>
<link:loc
xlink:type="locator"
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#rr_ProspectusTable"
xlink:label="ProspectusTable"/>
<link:loc
xlink:label="SupplementAbstract"
xlink:href="convertible-20140326.xsd#vanguard_SupplementAbstract"
xlink:type="locator"/>
<link:definitionArc
xbrldt:closed="true"
xlink:from="SupplementAbstract"
xlink:type="arc"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/all"
order="1.0"
xlink:to="ProspectusTable"
xbrldt:contextElement="segment"/>
<link:definitionArc
xbrldt:targetRole="http://xbrl.sec.gov/rr/role/Prospectus"
xlink:from="ProspectusTable"
xlink:type="arc"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension"
order="2.0"
xlink:to="DocumentInformationDocumentAxis"/>
<link:definitionArc
xbrldt:targetRole="http://xbrl.sec.gov/rr/role/Series"
xlink:to="LegalEntityAxis"
order="3.0"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension"
xlink:type="arc"
xlink:from="ProspectusTable"/>
<link:definitionArc
xlink:from="SupplementAbstract"
xlink:type="arc"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member"
order="4.0"
xlink:to="SupplementTextBlock"/></link:definitionLink>
<link:definitionLink
xlink:type="extended"
xlink:role="http://xbrl.sec.gov/rr/role/PerformanceTableData">
<link:loc
xlink:label="AverageAnnualReturnAbstract"
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#rr_AverageAnnualReturnAbstract"
xlink:type="locator"/>
<link:loc
xlink:type="locator"
xlink:href="convertible-20140326.xsd#vanguard_ComparativeBenchmark"
xlink:label="ComparativeBenchmark"/>
<link:definitionArc
xlink:from="AverageAnnualReturnAbstract"
xlink:type="arc"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member"
order="50.0"
xlink:to="ComparativeBenchmark"/></link:definitionLink>
<link:definitionLink
xlink:role="http://xbrl.sec.gov/rr/role/ShareholderFeesData"
xlink:type="extended">
<link:loc
xlink:type="locator"
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#rr_ShareholderFeesAbstract"
xlink:label="ShareholderFeesAbstract"/>
<link:loc
xlink:type="locator"
xlink:href="convertible-20140326.xsd#vanguard_ETFConversionFee"
xlink:label="ETFConversionFee"/>
<link:loc
xlink:label="TransactionFeeOnPurchases"
xlink:href="convertible-20140326.xsd#vanguard_TransactionFeeOnPurchases"
xlink:type="locator"/>
<link:loc
xlink:label="TransactionFeeOnReinvestedDividends"
xlink:href="convertible-20140326.xsd#vanguard_TransactionFeeOnReinvestedDividends"
xlink:type="locator"/>
<link:loc
xlink:type="locator"
xlink:href="convertible-20140326.xsd#vanguard_PurchaseFeeParenthetical"
xlink:label="PurchaseFeeParenthetical"/>
<link:loc
xlink:type="locator"
xlink:href="convertible-20140326.xsd#vanguard_RedemptionFeeParenthetical"
xlink:label="RedemptionFeeParenthetical"/>
<link:definitionArc
xlink:from="ShareholderFeesAbstract"
xlink:type="arc"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member"
order="51.0"
xlink:to="ETFConversionFee"/>
<link:definitionArc
xlink:from="ShareholderFeesAbstract"
xlink:type="arc"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member"
order="52.0"
xlink:to="TransactionFeeOnPurchases"/>
<link:definitionArc
xlink:to="TransactionFeeOnReinvestedDividends"
order="53.0"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member"
xlink:type="arc"
xlink:from="ShareholderFeesAbstract"/>
<link:definitionArc
xlink:from="ShareholderFeesAbstract"
xlink:type="arc"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member"
order="54.0"
xlink:to="PurchaseFeeParenthetical"/>
<link:definitionArc
xlink:to="RedemptionFeeParenthetical"
order="55.0"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member"
xlink:type="arc"
xlink:from="ShareholderFeesAbstract"/></link:definitionLink>
<link:definitionLink
xlink:type="extended"
xlink:role="http://xbrl.sec.gov/rr/role/RiskReturnDetailData">
<link:loc
xlink:label="RiskReturnAbstract"
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#rr_RiskReturnAbstract"
xlink:type="locator"/></link:definitionLink>
<link:definitionLink
xlink:type="extended"
xlink:role="http://xbrl.sec.gov/rr/role/OperatingExpensesData">
<link:loc
xlink:label="OperatingExpensesAbstract"
xlink:href="http://xbrl.sec.gov/rr/2012/rr-2012-01-31.xsd#rr_OperatingExpensesAbstract"
xlink:type="locator"/>
<link:loc
xlink:label="AquiredFundFeesExpensesExcludingAFFE"
xlink:href="convertible-20140326.xsd#vanguard_AquiredFundFeesExpensesExcludingAFFE"
xlink:type="locator"/>
<link:definitionArc
xlink:to="AquiredFundFeesExpensesExcludingAFFE"
order="301.0"
xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member"
xlink:type="arc"
xlink:from="OperatingExpensesAbstract"/></link:definitionLink>
<link:definitionLink
xlink:role="http://xbrl.sec.gov/rr/role/BarChartData"
xlink:type="extended"/>
<link:definitionLink
xlink:type="extended"
xlink:role="http://xbrl.sec.gov/rr/role/RiskReturn"/></link:linkbase>