Théir, a. pron.

(thâr, 12), a. pron. [A-S. thâra, thæra, properly gen. pl. of the, se. See THAT.] Of them;—employed in the sense of a pronominal adjective, denoting of or belonging to, or the possession by two or more; as, their voices; their garments; their houses; their land; their country. When standing alone, that is, when the word qualified by it is omitted, it has the form theirs; and, being used as a substitute for the adjective and the noun to which it refers, may be the nominative to a verb, or the object of a verb or preposition; as, our land is the most extensive, but theirs is the best cultivated. Here theirs stands as the representative of their land, and is the nominative to is.

Nothing but the name of zeal appears ’Twixt our best actions and the worst of theirs. Denham.