their

Their is a possessive determiner and a possessive pronoun in Modern English. It denotes ownership or association with a subject that is referred to by they, either as a plural group or as a gender-neutral singular.

As a possessive determiner, their appears before a noun: their house, their idea, their team won. It accompanies both plural subjects and the singular they. For example: They prepared their own meals.

As a possessive pronoun, theirs stands alone or follows a form of be: The book is theirs. That backpack is theirs. Theirs is a concise way to indicate ownership without repeating a noun.

The use of their reflects the current practice of gender-neutral language. They can serve as a gender-inclusive third-person pronoun for individuals whose gender is unknown or nonbinary, as well as for groups of people. This usage has historical roots in English and has become widely accepted in contemporary grammar and style guides.

Common confusions include mixing up their with there (place) and they're (they are). They are often distinguished by context and pronunciation, with correct spelling depending on whether a noun follows (determiner) or a noun is omitted (pronoun).

See also: pronouns, possessive forms.