(business, commerce) Someone not directly involved in a transaction; an entity beyond the seller (first party) and customer (second party).

(law) A derivative lawsuit brought by a defendant in an original lawsuit, claiming that another new party being brought in is responsible for or should share in the plaintiff's damages against the defendant.

A company that is contracted, by a bank etc., to conduct some part of a financial transaction process; especially a company that provides software or hardware for such a process

Of or relating to a third party.

(video games) To intervene in a fight between two players or teams, often allowing one to easy defeat both (sometimes seen as unfair).

plural of third-party claim

plural of third party processor