Dictionary
theirs
Pronunciation: (&thslash;ârz), [key]—
pron.
1. a form of the possessive case of
they used as a predicate adjective, after a noun or without a noun:
Are you a friend of theirs? It is theirs.
2. (used after an indefinite singular antecedent in place of the definite masculine form
his or the definite feminine form
hers):
I have my book; does everyone else have theirs?
3. that which belongs to them:
Theirs is the largest house on the block. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.