coheiress

noun

co·​heir·​ess ˌkō-ˈer-əs 

variants or co-heiress

plural coheiresses or co-heiresses

: an heiress who shares an inheritance with one or more other heirs or heiresses

Old Mr Vere is dead; and his daughters, who were coheiresses to his estate, are all married …

—Frances Sheridan

Word History

First Known Use

circa 1640, in the meaning defined above