Main Entry: theirs

Pronunciation: \ˈtherz\

Function: pronoun, singular or plural in construction

Date: 14th century

1 : that which belongs to them —used without a following noun as a pronoun equivalent in meaning to the adjective their
2 : his or hers : his, hers —used with an indefinite third person singular antecedent <I will do my part if everybody else will do theirs>