theirs

Theirs is the third-person plural possessive pronoun in English. It denotes ownership by a person or group previously mentioned or understood and typically functions as a pronoun that stands in for a noun phrase. For example, in The jackets are theirs, theirs replaces their jackets.

Theirs is used as a stand-alone pronoun and is not a determiner; the corresponding possessive determiner is their. For example, Their jackets are new uses the determiner form before a noun, while The jackets are theirs uses theirs after the noun. The set of independent possessive pronouns includes mine, yours, his, hers, ours, and theirs. The form theirs does not mark gender and can refer to either singular or plural ownership depending on context, including cases where a single person who uses they/them owns the item or where ownership lies with a group.

Etymology: Theirs derives from the Old English pronoun system and the genitive form of they, evolving into one of the English independent possessive pronouns. It shares its origin with the other forms in the same pronoun set.

Usage and style notes: In formal writing, use theirs to avoid repetition when the noun is understood or already specified; in dialogue or narrative, it can emphasize ownership. It is not used before a noun, which would require their as the determiner.