<link:linkbase 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" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd http://xbrl.org/2005/xbrldt http://www.xbrl.org/2005/xbrldt-2005.xsd" xmlns:cik0001084380="http://TIAA.com/20260331">
	<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/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: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://www.xbrl.org/2009/arcrole/dep-concept-deprecatedConcept" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/arcrole/deprecated-2009-12-16.xsd#dep-concept-deprecatedConcept" />
	<link:roleRef roleURI="http://TIAA.com/20260331/role/RRRiskTable3" xlink:type="simple" xlink:href="c485bpos-20260721.xsd#RRRiskTable3" />
	<link:roleRef roleURI="http://TIAA.com/20260331/role/RRRiskTable5" xlink:type="simple" xlink:href="c485bpos-20260721.xsd#RRRiskTable5" />
	<link:roleRef roleURI="http://TIAA.com/20260331/role/RRRiskTable7" xlink:type="simple" xlink:href="c485bpos-20260721.xsd#RRRiskTable7" />
	<link:roleRef roleURI="http://TIAA.com/20260331/role/RRRiskTable9" xlink:type="simple" xlink:href="c485bpos-20260721.xsd#RRRiskTable9" />
	<link:roleRef roleURI="http://TIAA.com/20260331/role/RRRiskTable11" xlink:type="simple" xlink:href="c485bpos-20260721.xsd#RRRiskTable11" />
	<link:roleRef roleURI="http://TIAA.com/20260331/role/RRRiskTable13" xlink:type="simple" xlink:href="c485bpos-20260721.xsd#RRRiskTable13" />
	<link:roleRef roleURI="http://TIAA.com/20260331/role/RRRiskTable15" xlink:type="simple" xlink:href="c485bpos-20260721.xsd#RRRiskTable15" />
	<link:roleRef roleURI="http://TIAA.com/20260331/role/RRRiskTable17" xlink:type="simple" xlink:href="c485bpos-20260721.xsd#RRRiskTable17" />
	<link:roleRef roleURI="http://TIAA.com/20260331/role/RRRiskTable19" xlink:type="simple" xlink:href="c485bpos-20260721.xsd#RRRiskTable19" />
	<link:roleRef roleURI="http://TIAA.com/20260331/role/RRRiskTable21" xlink:type="simple" xlink:href="c485bpos-20260721.xsd#RRRiskTable21" />
	<link:roleRef roleURI="http://TIAA.com/20260331/role/RRRiskTable23" xlink:type="simple" xlink:href="c485bpos-20260721.xsd#RRRiskTable23" />
	<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: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:roleRef roleURI="http://xbrl.sec.gov/rr/role/ShareholderFeesData" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#ShareholderFeesData" />
	<link:roleRef roleURI="http://xbrl.sec.gov/rr/role/OperatingExpensesData" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#OperatingExpensesData" />
	<link:roleRef roleURI="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#PerformanceMeasureOnly" />
	<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:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/SeriesOnly">
		<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain" xlink:label="EntityDomain" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_S000026500Member" xlink:label="S000026500Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000026500Member" order="1.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_S000005372Member" xlink:label="S000005372Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000005372Member" order="2.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_S000038169Member" xlink:label="S000038169Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000038169Member" order="3.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_S000012198Member" xlink:label="S000012198Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000012198Member" order="4.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_S000012199Member" xlink:label="S000012199Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000012199Member" order="5.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_S000063522Member" xlink:label="S000063522Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000063522Member" order="6.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_S000012196Member" xlink:label="S000012196Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000012196Member" order="7.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_S000063523Member" xlink:label="S000063523Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000063523Member" order="8.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_S000012195Member" xlink:label="S000012195Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000012195Member" order="9.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_S000050278Member" xlink:label="S000050278Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000050278Member" order="10.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_S000005374Member" xlink:label="S000005374Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000005374Member" order="11.0" />
	</link:definitionLink>
	<link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/ClassOnly">
		<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_ShareClassDomain" xlink:label="ShareClassDomain" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000079526Member" xlink:label="C000079526Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000079526Member" order="1.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000162579Member" xlink:label="C000162579Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000162579Member" order="2.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000079525Member" xlink:label="C000079525Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000079525Member" order="3.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000079523Member" xlink:label="C000079523Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000079523Member" order="4.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000079524Member" xlink:label="C000079524Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000079524Member" order="5.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000202762Member" xlink:label="C000202762Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000202762Member" order="6.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033992Member" xlink:label="C000033992Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033992Member" order="7.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000162549Member" xlink:label="C000162549Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000162549Member" order="8.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000079556Member" xlink:label="C000079556Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000079556Member" order="9.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000014635Member" xlink:label="C000014635Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000014635Member" order="10.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033991Member" xlink:label="C000033991Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033991Member" order="11.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000202747Member" xlink:label="C000202747Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000202747Member" order="12.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000117723Member" xlink:label="C000117723Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000117723Member" order="13.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000162598Member" xlink:label="C000162598Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000162598Member" order="14.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000117722Member" xlink:label="C000117722Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000117722Member" order="15.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000117721Member" xlink:label="C000117721Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000117721Member" order="16.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000117724Member" xlink:label="C000117724Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000117724Member" order="17.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033283Member" xlink:label="C000033283Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033283Member" order="18.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000162569Member" xlink:label="C000162569Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000162569Member" order="19.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000079574Member" xlink:label="C000079574Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000079574Member" order="20.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033285Member" xlink:label="C000033285Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033285Member" order="21.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033284Member" xlink:label="C000033284Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033284Member" order="22.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000202758Member" xlink:label="C000202758Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000202758Member" order="23.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033286Member" xlink:label="C000033286Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033286Member" order="24.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000162570Member" xlink:label="C000162570Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000162570Member" order="25.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033287Member" xlink:label="C000033287Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033287Member" order="26.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000205813Member" xlink:label="C000205813Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000205813Member" order="27.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000205815Member" xlink:label="C000205815Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000205815Member" order="28.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000205812Member" xlink:label="C000205812Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000205812Member" order="29.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000205811Member" xlink:label="C000205811Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000205811Member" order="30.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000205814Member" xlink:label="C000205814Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000205814Member" order="31.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033277Member" xlink:label="C000033277Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033277Member" order="32.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000162567Member" xlink:label="C000162567Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000162567Member" order="33.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000079572Member" xlink:label="C000079572Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000079572Member" order="34.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033279Member" xlink:label="C000033279Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033279Member" order="35.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033278Member" xlink:label="C000033278Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033278Member" order="36.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000202756Member" xlink:label="C000202756Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000202756Member" order="37.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000205818Member" xlink:label="C000205818Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000205818Member" order="38.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000205820Member" xlink:label="C000205820Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000205820Member" order="39.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000205817Member" xlink:label="C000205817Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000205817Member" order="40.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000205816Member" xlink:label="C000205816Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000205816Member" order="41.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000205819Member" xlink:label="C000205819Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000205819Member" order="42.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033274Member" xlink:label="C000033274Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033274Member" order="43.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000162566Member" xlink:label="C000162566Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000162566Member" order="44.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000079571Member" xlink:label="C000079571Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000079571Member" order="45.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033276Member" xlink:label="C000033276Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033276Member" order="46.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033275Member" xlink:label="C000033275Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033275Member" order="47.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000202755Member" xlink:label="C000202755Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000202755Member" order="48.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000158752Member" xlink:label="C000158752Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000158752Member" order="49.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000162603Member" xlink:label="C000162603Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000162603Member" order="50.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000158751Member" xlink:label="C000158751Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000158751Member" order="51.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000158750Member" xlink:label="C000158750Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000158750Member" order="52.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000158753Member" xlink:label="C000158753Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000158753Member" order="53.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000202767Member" xlink:label="C000202767Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000202767Member" order="54.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033995Member" xlink:label="C000033995Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033995Member" order="55.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000162551Member" xlink:label="C000162551Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000162551Member" order="56.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000079558Member" xlink:label="C000079558Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000079558Member" order="57.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000014638Member" xlink:label="C000014638Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000014638Member" order="58.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000033994Member" xlink:label="C000033994Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000033994Member" order="59.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_C000202749Member" xlink:label="C000202749Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000202749Member" order="60.0" />
	</link:definitionLink>
	<link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly">
		<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_PerformanceMeasureDomain" xlink:label="PerformanceMeasureDomain" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_BloombergUSAggregateBondIndex31Member" xlink:label="BloombergUSAggregateBondIndex31Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergUSAggregateBondIndex31Member" order="1.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_BloombergUSAggregateBondIndex32Member" xlink:label="BloombergUSAggregateBondIndex32Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergUSAggregateBondIndex32Member" order="2.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_BloombergUSAggregateBondIndex33Member" xlink:label="BloombergUSAggregateBondIndex33Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergUSAggregateBondIndex33Member" order="3.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_BloombergUSAggregateBondIndex34Member" xlink:label="BloombergUSAggregateBondIndex34Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergUSAggregateBondIndex34Member" order="4.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_BloombergMunicipalBondIndex35Member" xlink:label="BloombergMunicipalBondIndex35Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergMunicipalBondIndex35Member" order="5.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_Bloomberg10-YearMunicipalBondIndex36Member" xlink:label="Bloomberg10-YearMunicipalBondIndex36Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="Bloomberg10-YearMunicipalBondIndex36Member" order="6.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_BloombergUSAggregateBondIndex37Member" xlink:label="BloombergUSAggregateBondIndex37Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergUSAggregateBondIndex37Member" order="7.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_BloombergMSCIUSGreenBondIndex38Member" xlink:label="BloombergMSCIUSGreenBondIndex38Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergMSCIUSGreenBondIndex38Member" order="8.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_BloombergUSAggregateBondIndex39Member" xlink:label="BloombergUSAggregateBondIndex39Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergUSAggregateBondIndex39Member" order="9.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_ICEBofABB-BUSCashPayHighYieldConstrainedIndex310Member" xlink:label="ICEBofABB-BUSCashPayHighYieldConstrainedIndex310Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="ICEBofABB-BUSCashPayHighYieldConstrainedIndex310Member" order="10.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_BloombergUSAggregateBondIndex311Member" xlink:label="BloombergUSAggregateBondIndex311Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergUSAggregateBondIndex311Member" order="11.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_BloombergUS1-3YearGovernmentCreditBondIndex312Member" xlink:label="BloombergUS1-3YearGovernmentCreditBondIndex312Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergUS1-3YearGovernmentCreditBondIndex312Member" order="12.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_BloombergUSAggregateBondIndex313Member" xlink:label="BloombergUSAggregateBondIndex313Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergUSAggregateBondIndex313Member" order="13.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_BloombergUS1-3YearGovernmentCreditBondIndex314Member" xlink:label="BloombergUS1-3YearGovernmentCreditBondIndex314Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergUS1-3YearGovernmentCreditBondIndex314Member" order="14.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_BloombergUSAggregateBondIndex315Member" xlink:label="BloombergUSAggregateBondIndex315Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergUSAggregateBondIndex315Member" order="15.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_BloombergUS1-3YearGovernmentCreditBondIndex316Member" xlink:label="BloombergUS1-3YearGovernmentCreditBondIndex316Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergUS1-3YearGovernmentCreditBondIndex316Member" order="16.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_iMoneyNetMoneyFundAveragesAllGovernment317Member" xlink:label="iMoneyNetMoneyFundAveragesAllGovernment317Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="iMoneyNetMoneyFundAveragesAllGovernment317Member" order="17.0" />
	</link:definitionLink>
	<link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/RiskOnly">
		<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_AllRisksMember" xlink:label="AllRisksMember" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_Principalinvestmentrisks2Member" xlink:label="Principalinvestmentrisks2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="Principalinvestmentrisks2Member" order="1.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_InterestRateRiskatypeofMarketRisk2Member" xlink:label="InterestRateRiskatypeofMarketRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="InterestRateRiskatypeofMarketRisk2Member" order="2.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_PrepaymentRisk2Member" xlink:label="PrepaymentRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="PrepaymentRisk2Member" order="3.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_ExtensionRisk2Member" xlink:label="ExtensionRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="ExtensionRisk2Member" order="4.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_IssuerRiskoftencalledFinancialRisk2Member" xlink:label="IssuerRiskoftencalledFinancialRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="IssuerRiskoftencalledFinancialRisk2Member" order="5.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_CreditRiskatypeofIssuerRisk2Member" xlink:label="CreditRiskatypeofIssuerRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="CreditRiskatypeofIssuerRisk2Member" order="6.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_CreditSpreadRisk2Member" xlink:label="CreditSpreadRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="CreditSpreadRisk2Member" order="7.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_IncomeVolatilityRisk2Member" xlink:label="IncomeVolatilityRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="IncomeVolatilityRisk2Member" order="8.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_MarketVolatilityLiquidityandValuationRisktypesofMarketRisk2Member" xlink:label="MarketVolatilityLiquidityandValuationRisktypesofMarketRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="MarketVolatilityLiquidityandValuationRisktypesofMarketRisk2Member" order="9.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_IndexRisk2Member" xlink:label="IndexRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="IndexRisk2Member" order="10.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_Fixed-IncomeForeignInvestmentRisk2Member" xlink:label="Fixed-IncomeForeignInvestmentRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="Fixed-IncomeForeignInvestmentRisk2Member" order="11.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_USGovernmentSecuritiesRisk2Member" xlink:label="USGovernmentSecuritiesRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="USGovernmentSecuritiesRisk2Member" order="12.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_IlliquidInvestmentsRisk2Member" xlink:label="IlliquidInvestmentsRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="IlliquidInvestmentsRisk2Member" order="13.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_DowngradeRisk2Member" xlink:label="DowngradeRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="DowngradeRisk2Member" order="14.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_CallRisk2Member" xlink:label="CallRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="CallRisk2Member" order="15.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_FloatingandVariableRateSecuritiesRisk2Member" xlink:label="FloatingandVariableRateSecuritiesRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="FloatingandVariableRateSecuritiesRisk2Member" order="16.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_Non-DiversificationRisk2Member" xlink:label="Non-DiversificationRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="Non-DiversificationRisk2Member" order="17.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_ActiveManagementRisk2Member" xlink:label="ActiveManagementRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="ActiveManagementRisk2Member" order="18.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_MortgageRollRisk2Member" xlink:label="MortgageRollRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="MortgageRollRisk2Member" order="19.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_Non-Investment-GradeSecuritiesRisk2Member" xlink:label="Non-Investment-GradeSecuritiesRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="Non-Investment-GradeSecuritiesRisk2Member" order="20.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_SeniorLoanRisk2Member" xlink:label="SeniorLoanRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="SeniorLoanRisk2Member" order="21.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_EmergingMarketsRisk2Member" xlink:label="EmergingMarketsRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="EmergingMarketsRisk2Member" order="22.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_PortfolioTurnoverRisk2Member" xlink:label="PortfolioTurnoverRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="PortfolioTurnoverRisk2Member" order="23.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_DerivativesRisk2Member" xlink:label="DerivativesRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="DerivativesRisk2Member" order="24.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_ESGCriteriaandImpactRisk2Member" xlink:label="ESGCriteriaandImpactRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="ESGCriteriaandImpactRisk2Member" order="25.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_RegulationSSecuritiesRisk2Member" xlink:label="RegulationSSecuritiesRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="RegulationSSecuritiesRisk2Member" order="26.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_RisksofInvestmentsintheFundsTEFRABondSubsidiary2Member" xlink:label="RisksofInvestmentsintheFundsTEFRABondSubsidiary2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="RisksofInvestmentsintheFundsTEFRABondSubsidiary2Member" order="27.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_RisksofInvestmentsintheFundsWhollyOwnedSubsidiaries2Member" xlink:label="RisksofInvestmentsintheFundsWhollyOwnedSubsidiaries2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="RisksofInvestmentsintheFundsWhollyOwnedSubsidiaries2Member" order="28.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_StateandMunicipalInvestmentRisk2Member" xlink:label="StateandMunicipalInvestmentRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="StateandMunicipalInvestmentRisk2Member" order="29.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_TaxRisk2Member" xlink:label="TaxRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="TaxRisk2Member" order="30.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_GreenInvestmentRisk2Member" xlink:label="GreenInvestmentRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="GreenInvestmentRisk2Member" order="31.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_RisksofInvestmentsintheFundsWhollyOwnedSubsidiary2Member" xlink:label="RisksofInvestmentsintheFundsWhollyOwnedSubsidiary2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="RisksofInvestmentsintheFundsWhollyOwnedSubsidiary2Member" order="32.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260721.xsd#cik0001084380_CurrentIncomeRisk2Member" xlink:label="CurrentIncomeRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="CurrentIncomeRisk2Member" order="33.0" />
	</link:definitionLink>
</link:linkbase>