Charter's rhymes with:
charters, carter's, carters, charters, garters, martyrs, nonstarters, quarters', starters, tartars
Charter's sounds like:
carithers, carothers, carrithers, carrothers, carruthers, carter's, carters, caruthers, charterhouse, charters, chartres, chartreuse, corridors, courter's, courtiers, craters, creators, creatures, creditors, creditors', critters, crothers, crowther's, crowthers, curator's, curators, czartoryski