their | TKG English Learner's Dictionary

theirdeterminer

American /ðɛr/ British /ðeə/ Their, there, and they're all sound the same, like the word air with a th sound at the start.

very commondefining vocabulary

belonging to thembelonging to or connected with the people, animals, or things already mentioned
Their goes directly before a noun and does not change for a plural noun: their house, their ideas. It is also common as a way to refer back to one person whose sex is not stated or not known: someone left their bag here. The same idea used alone, without a following noun, is a different word, theirs (this house is theirs), a separate entry.
- Our neighbors painted their fence last weekend.
- The students handed in their homework on time.
- Someone left their phone on the bus.
- The company announced their new plans today.
Compare his; her

Word family

Usage

Their never changes for number. The independent possessive, used without a following noun, is a different word, theirs (this is theirs). Do not confuse their with there (a place) and they're (short for they are); all three sound the same.

Common mistakes

Their going to the party tonight. They're going to the party tonight.
They're is short for they are; their shows possession.

See also theirs (the independent possessive, used without a following noun: this is theirs)

For translators

Grammar trap Their is increasingly used for one person whose sex is not stated or not known (someone forgot their umbrella), a use many other languages do not have with a word that looks plural.