Two alike or identical things taken together; often followed by of. • One of the constituent items that make up a pair. • Two people in a relationship, partnership or friendship. • Used with binary nouns (often in the plural to indicate multiple instances, since such nouns are plural only, except in some technical contexts). • A couple of working animals attached to work together, as by a yoke. • A poker hand that contains two cards of identical rank, which cannot also count as a better hand. • A score of zero runs (a duck) in both innings of a two-innings match. • A double play, two outs recorded in one play. • A doubleheader, two games played on the same day between the same teams. • A boat for two sweep rowers. • A pair of breasts. • A pair of testicles. • The exclusion of one member of a parliamentary party from a vote, if a member of the other party is absent for important personal reasons. • Two members of opposite parties or opinion, as in a parliamentary body, who mutually agree not to vote on a given question, or on issues of a party nature during a specified time. • A number of things resembling one another, or belonging together; a set. • In a mechanism, two elements, or bodies, which are so applied to each other as to mutually constrain relative motion; named in accordance with the motion it permits, as in turning pair, sliding pair, twisting pair.