<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019cdd7d-77f5-7a57-840a-a140c0683728,g:f6b1b458-6262-4102-baf0-ae84e0f75a52-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <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-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <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: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:roleRef roleURI="http://xbrl.sec.gov/oef/role/SeriesOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#SeriesOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/oef/role/SeriesOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_S000101830Member_019cdd7d-77f5-741d-ab32-41f51ba4a04d" xlink:href="ck0001137360-20260320.xsd#ck0001137360_S000101830Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain" xlink:to="loc_ck0001137360_S000101830Member_019cdd7d-77f5-741d-ab32-41f51ba4a04d" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/oef/role/ClassOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#ClassOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/oef/role/ClassOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_oef_ShareClassDomain" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_ShareClassDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_C000272139Member_019cdd7d-77f5-72d3-90a4-f2a0f1e3640c" xlink:href="ck0001137360-20260320.xsd#ck0001137360_C000272139Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_ShareClassDomain" xlink:to="loc_ck0001137360_C000272139Member_019cdd7d-77f5-72d3-90a4-f2a0f1e3640c" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/rr/role/RiskOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#RiskOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/rr/role/RiskOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_oef_AllRisksMember" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_AllRisksMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_EmergingMarketIssuersRiskMember_019ce32b-1b1e-79d1-9e1f-f359fd107942" xlink:href="ck0001137360-20260320.xsd#ck0001137360_EmergingMarketIssuersRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_EmergingMarketIssuersRiskMember_019ce32b-1b1e-79d1-9e1f-f359fd107942" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_EmergingMarketIssuersRiskSecuritiesMarketRiskMember_019ce2ce-5b40-7526-bdad-7a2de1362872" xlink:href="ck0001137360-20260320.xsd#ck0001137360_EmergingMarketIssuersRiskSecuritiesMarketRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_EmergingMarketIssuersRiskSecuritiesMarketRiskMember_019ce2ce-5b40-7526-bdad-7a2de1362872" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_EmergingMarketIssuersRiskPoliticalAndEconomicRiskMember_019ce2cf-d48f-76c7-80cb-6b50eded0d29" xlink:href="ck0001137360-20260320.xsd#ck0001137360_EmergingMarketIssuersRiskPoliticalAndEconomicRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_EmergingMarketIssuersRiskPoliticalAndEconomicRiskMember_019ce2cf-d48f-76c7-80cb-6b50eded0d29" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_EmergingMarketIssuersRiskInvestmentAndRepatriationRestrictionsMember_019ce2d1-f5f5-7645-8e63-71467940e49a" xlink:href="ck0001137360-20260320.xsd#ck0001137360_EmergingMarketIssuersRiskInvestmentAndRepatriationRestrictionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_EmergingMarketIssuersRiskInvestmentAndRepatriationRestrictionsMember_019ce2d1-f5f5-7645-8e63-71467940e49a" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_EmergingMarketIssuersRiskLimitedDisclosureAboutEmergingMarketIssuersRiskMember_019ce2d2-b225-713c-a39e-2c8a0e3717a2" xlink:href="ck0001137360-20260320.xsd#ck0001137360_EmergingMarketIssuersRiskLimitedDisclosureAboutEmergingMarketIssuersRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_EmergingMarketIssuersRiskLimitedDisclosureAboutEmergingMarketIssuersRiskMember_019ce2d2-b225-713c-a39e-2c8a0e3717a2" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_EmergingMarketIssuersRiskForeignCurrencyRiskConsiderationsMember_019ce2d3-9fc2-7475-972f-361d92e25ab1" xlink:href="ck0001137360-20260320.xsd#ck0001137360_EmergingMarketIssuersRiskForeignCurrencyRiskConsiderationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_EmergingMarketIssuersRiskForeignCurrencyRiskConsiderationsMember_019ce2d3-9fc2-7475-972f-361d92e25ab1" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_EmergingMarketIssuersRiskOperationalAndSettlementRiskMember_019ce2d4-528e-7763-9416-3e2054ced9ba" xlink:href="ck0001137360-20260320.xsd#ck0001137360_EmergingMarketIssuersRiskOperationalAndSettlementRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_EmergingMarketIssuersRiskOperationalAndSettlementRiskMember_019ce2d4-528e-7763-9416-3e2054ced9ba" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_EmergingMarketIssuersRiskCorporateAndSecuritiesLawsMember_019ce2db-ecf3-7742-9b36-a08f02653e8c" xlink:href="ck0001137360-20260320.xsd#ck0001137360_EmergingMarketIssuersRiskCorporateAndSecuritiesLawsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_EmergingMarketIssuersRiskCorporateAndSecuritiesLawsMember_019ce2db-ecf3-7742-9b36-a08f02653e8c" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_ForeignSecuritiesRiskMember_019ce919-c3b9-7cd7-a308-0f5d43f341b5" xlink:href="ck0001137360-20260320.xsd#ck0001137360_ForeignSecuritiesRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_ForeignSecuritiesRiskMember_019ce919-c3b9-7cd7-a308-0f5d43f341b5" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_InformationTechnologySectorRiskMember_019ce2cc-b1f3-7dfd-95c7-45b3230ff757" xlink:href="ck0001137360-20260320.xsd#ck0001137360_InformationTechnologySectorRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_InformationTechnologySectorRiskMember_019ce2cc-b1f3-7dfd-95c7-45b3230ff757" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_FinancialsSectorRiskMember_019ce2e2-3016-7123-af83-52e76c074d93" xlink:href="ck0001137360-20260320.xsd#ck0001137360_FinancialsSectorRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_FinancialsSectorRiskMember_019ce2e2-3016-7123-af83-52e76c074d93" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_BasicMaterialsSectorRiskMember_019ce2e3-ff89-78d1-b6b3-e7bfbd445da4" xlink:href="ck0001137360-20260320.xsd#ck0001137360_BasicMaterialsSectorRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_BasicMaterialsSectorRiskMember_019ce2e3-ff89-78d1-b6b3-e7bfbd445da4" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_SpecialRiskConsiderationsOfInvestingInChineseIssuersMember_019ce2e4-e10f-7ac6-ad0e-f8c7bd2632f1" xlink:href="ck0001137360-20260320.xsd#ck0001137360_SpecialRiskConsiderationsOfInvestingInChineseIssuersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_SpecialRiskConsiderationsOfInvestingInChineseIssuersMember_019ce2e4-e10f-7ac6-ad0e-f8c7bd2632f1" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_SpecialRiskConsiderationsOfInvestingInIndianIssuersMember_019ce2e6-223d-71d6-99eb-d6b909f7e94e" xlink:href="ck0001137360-20260320.xsd#ck0001137360_SpecialRiskConsiderationsOfInvestingInIndianIssuersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_SpecialRiskConsiderationsOfInvestingInIndianIssuersMember_019ce2e6-223d-71d6-99eb-d6b909f7e94e" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_SpecialRiskConsiderationsOfInvestingInSouthKoreanIssuersMember_019ce2e7-556c-7f9a-a7ae-2bd9b7d20a19" xlink:href="ck0001137360-20260320.xsd#ck0001137360_SpecialRiskConsiderationsOfInvestingInSouthKoreanIssuersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_SpecialRiskConsiderationsOfInvestingInSouthKoreanIssuersMember_019ce2e7-556c-7f9a-a7ae-2bd9b7d20a19" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_SpecialRiskConsiderationsOfInvestingInTaiwaneseIssuersMember_019ce2e8-4ba2-7aaa-985b-5522c774b3b3" xlink:href="ck0001137360-20260320.xsd#ck0001137360_SpecialRiskConsiderationsOfInvestingInTaiwaneseIssuersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_SpecialRiskConsiderationsOfInvestingInTaiwaneseIssuersMember_019ce2e8-4ba2-7aaa-985b-5522c774b3b3" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_CashTransactionsRiskMember_019ce2e8-d42c-748a-b8e1-211f140af4c8" xlink:href="ck0001137360-20260320.xsd#ck0001137360_CashTransactionsRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_CashTransactionsRiskMember_019ce2e8-d42c-748a-b8e1-211f140af4c8" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_DepositaryReceiptsRiskMember_019ce2e9-58cf-73fb-bdd3-62019bad6cc0" xlink:href="ck0001137360-20260320.xsd#ck0001137360_DepositaryReceiptsRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_DepositaryReceiptsRiskMember_019ce2e9-58cf-73fb-bdd3-62019bad6cc0" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_EquitySecuritiesRiskMember_019ce2e9-cc5d-7c63-a584-a519e11d64fa" xlink:href="ck0001137360-20260320.xsd#ck0001137360_EquitySecuritiesRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_EquitySecuritiesRiskMember_019ce2e9-cc5d-7c63-a584-a519e11d64fa" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_IssuerSpecificChangesRiskMember_019ce2ea-63c5-7768-8164-402f38f5906c" xlink:href="ck0001137360-20260320.xsd#ck0001137360_IssuerSpecificChangesRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_IssuerSpecificChangesRiskMember_019ce2ea-63c5-7768-8164-402f38f5906c" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_LargeCapitalizationCompaniesRiskMember_019ce2ea-ecff-775a-9ea2-0fef78bc8135" xlink:href="ck0001137360-20260320.xsd#ck0001137360_LargeCapitalizationCompaniesRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_LargeCapitalizationCompaniesRiskMember_019ce2ea-ecff-775a-9ea2-0fef78bc8135" xlink:type="arc" order="29"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_MediumCapitalizationCompaniesRiskMember_019ce2eb-a4c9-7d82-a849-8d3699bbdb34" xlink:href="ck0001137360-20260320.xsd#ck0001137360_MediumCapitalizationCompaniesRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_MediumCapitalizationCompaniesRiskMember_019ce2eb-a4c9-7d82-a849-8d3699bbdb34" xlink:type="arc" order="30"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_MarketRiskMember_019ce2ec-2e37-70c7-8103-e92abbe53226" xlink:href="ck0001137360-20260320.xsd#ck0001137360_MarketRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_MarketRiskMember_019ce2ec-2e37-70c7-8103-e92abbe53226" xlink:type="arc" order="31"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_OperationalRiskMember_019ce2ec-dca9-76c1-b04d-35f25fd03f7d" xlink:href="ck0001137360-20260320.xsd#ck0001137360_OperationalRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_OperationalRiskMember_019ce2ec-dca9-76c1-b04d-35f25fd03f7d" xlink:type="arc" order="32"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_IndexTrackingRiskMember_019ce2ed-5804-7e33-bdea-5059e00846db" xlink:href="ck0001137360-20260320.xsd#ck0001137360_IndexTrackingRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_IndexTrackingRiskMember_019ce2ed-5804-7e33-bdea-5059e00846db" xlink:type="arc" order="33"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_AuthorizedParticipantConcentrationRiskMember_019ce2ee-0947-774f-9a8e-7df2b8f4e3c5" xlink:href="ck0001137360-20260320.xsd#ck0001137360_AuthorizedParticipantConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_AuthorizedParticipantConcentrationRiskMember_019ce2ee-0947-774f-9a8e-7df2b8f4e3c5" xlink:type="arc" order="34"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_NewFundRiskMember_019ce2ee-900f-7dba-9864-9878d418c5c1" xlink:href="ck0001137360-20260320.xsd#ck0001137360_NewFundRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_NewFundRiskMember_019ce2ee-900f-7dba-9864-9878d418c5c1" xlink:type="arc" order="35"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_NoGuaranteeOfActiveTradingMarketRiskMember_019ce2ee-ff77-72a6-9155-36e98c280f58" xlink:href="ck0001137360-20260320.xsd#ck0001137360_NoGuaranteeOfActiveTradingMarketRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_NoGuaranteeOfActiveTradingMarketRiskMember_019ce2ee-ff77-72a6-9155-36e98c280f58" xlink:type="arc" order="36"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_TradingIssuesRiskMember_019ce2ef-5dd4-7046-8d3b-593dd574bc55" xlink:href="ck0001137360-20260320.xsd#ck0001137360_TradingIssuesRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_TradingIssuesRiskMember_019ce2ef-5dd4-7046-8d3b-593dd574bc55" xlink:type="arc" order="37"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_PassiveManagementRiskMember_019ce2ef-c63e-75c4-984b-5cedfca7f6a2" xlink:href="ck0001137360-20260320.xsd#ck0001137360_PassiveManagementRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_PassiveManagementRiskMember_019ce2ef-c63e-75c4-984b-5cedfca7f6a2" xlink:type="arc" order="38"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_FundSharesTradingPremiumDiscountRiskAndLiquidityOfFundSharesMember_019ce2f0-60e4-7066-b733-49adad9da663" xlink:href="ck0001137360-20260320.xsd#ck0001137360_FundSharesTradingPremiumDiscountRiskAndLiquidityOfFundSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_FundSharesTradingPremiumDiscountRiskAndLiquidityOfFundSharesMember_019ce2f0-60e4-7066-b733-49adad9da663" xlink:type="arc" order="39"/>
    <link:loc xlink:type="locator" xlink:label="loc_ck0001137360_IndexRelatedConcentrationRiskMember_019ce2f1-2aaf-7643-859c-9ef4d4773458" xlink:href="ck0001137360-20260320.xsd#ck0001137360_IndexRelatedConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oef_AllRisksMember" xlink:to="loc_ck0001137360_IndexRelatedConcentrationRiskMember_019ce2f1-2aaf-7643-859c-9ef4d4773458" xlink:type="arc" order="40"/>
  </link:definitionLink>
</link:linkbase>
