pair

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Two corresponding persons or items, similar in form or function and matched or associated: a pair of shoes.
2. n. One object composed of two joined, similar parts that are dependent upon each other: a pair of pliers.
3. n. Two persons who are married, engaged, or dating.
4. n. Two persons who have something in common and are considered together: a pair of hunters.
5. n. Two mated animals.
6. n. Two animals joined together in work.
7. n. Games Two playing cards of the same denomination.
8. n. Two members of a deliberative body with opposing opinions on a given issue who agree to abstain from voting on the issue, thereby offsetting each other.
9. n. Chemistry An electron pair.
10. v. To arrange in sets of two; couple.
11. v. To join in a pair; mate.
12. v. To provide a partner for.
13. v. To form pairs or a pair.
14. v. To join in marriage; mate.

Century Dictionary and Cyclopedia

1. n. Two things of a kind, similar in form, identical in purpose, and matched or used together: as, a pair of gloves; a pair of shoes.
2. n. A single thing composed essentially of two pieces or parts which are used only in combination and named only in the plural: as, a pair of scissors, trousers, or spectacles.
3. n. A couple; a brace; a span: as, a pair of pistols; a pair of horses.
4. n. Specifically.
5. n. A married couple; in general, two mated animals of any kind.
6. n. A set of like or equal things: restricted to a few (mostly obsolete) phrases: as, a pair (or pack) of cards; a pair (or flight) of stairs; a pair of organs (that is, a set of organ-pipes, hence an organ); a pair of gallows (that is, a gibbet); a pair of beads (see bead).
7. n. In archery, a set of three arrows.
8. n. In mining, a set or gang of men working together at the same hours.
9. n. In deliberative bodies, two members belonging to opposing parties who for their own convenience (as to permit one or both of them to be absent) arrange with each other to refrain from voting for a specified time or on a specified question, thus nullifying a vote on each side; also, the arrangement thus effected. See pairing.
10. n. In poker, two of the same denomination, without regard to suit or color: as, a pair of aces or deuces.
11. n. See the adjectives.
12. n. =Syn. 1-3. Pair, Couple, Yoke, Brace, Dyad, Duad. Pair and couple properly express two individuals or unities naturally or habitually going together or making a set: as, a pair of horses, gloves, oars; a wedded pair; a loving couple; but pair also means two things alike and put together, and couple has by colloquial use come to be often applied to two, however accidentally brought together: as, give him a couple of apples. Yoke, on the other hand, applies only to two animals customarily yoked together: as, a yoke of oxen. Brace is rather a hunters' term, with limited and peculiar application: as, a brace of partridges, pistols, slugs. Dyad is used in philosophical and mathematical language only. Duad is a special mathematical word signifying an unordered pair.
13. To form a pair or pairs; specifically, to be joined in pairs as birds are in the breeding season; mate; couple.
14. To suit; fit; match.
15. To abstain from voting by arrangement with a member of the opposite party to do the same: said of members of deliberative assemblies. See pairing.
16. To join in couples; specifically, to cause to mate: as, to pair a canary with a siskin.
17. To unite or assort in twos as well suited to each other.
18. To impair.
19. To become impaired; deteriorate.
20. n. In roulette, an even number.
21. n. In mech., two parts or pieces, each of which acts against the other to hold it in position or to restrain its motion, as a bearing and journal, or a screw and nut.
22. In cribbage, to match (the card last played by the adversary).

Wiktionary

1. n. Two similar or identical things taken together; often followed by of.
2. n. Two people in a relationship, partnership (especially sexual) or friendship.
3. n. Used with binary nouns (often in the plural to indicate multiple instances, since such nouns are plurale tantum)
4. n. A couple of working animals attached to work together, as by a yoke.
5. n. A poker hand that contains of two cards of identical rank, which cannot also count as a better hand.
6. n. A score of zero runs (a duck) in both innings of a two-innings match
7. n. A double play, two outs recorded in one play
8. n. A doubleheader, two games played on the same day between the same teams
9. n. A pair of breasts
10. v. To group into sets of two.
11. v. To bring two (animals, notably dogs) together for mating.

GNU Webster's 1913

1. n. A number of things resembling one another, or belonging together; a set. “A pair of beads.” Chaucer. Beau. & Fl. “Four pair of stairs.” Macaulay. [Now mostly or quite disused.]
2. n. Two things of a kind, similar in form, suited to each other, and intended to be used together
3. n. Two of a sort; a span; a yoke; a couple; a brace
4. n. A married couple; a man and wife.
5. n. A single thing, composed of two pieces fitted to each other and used together
6. n. Two members of opposite parties or opinion, as in a parliamentary body, who mutually agree not to vote on a given question (in order, for example, to allow the members to be absent during the vote without affecting the outcome of the vote), or on issues of a party nature during a specified time.
7. n. In a mechanism, two elements, or bodies, which are so applied to each other as to mutually constrain relative motion.
8. v. To be joined in pairs; to couple; to mate, as for breeding.
9. v. To suit; to fit, as a counterpart.
10. v. Same as To pair off. See phrase below.
11. v. To unite in couples; to form a pair of; to bring together, as things which belong together, or which complement, or are adapted to one another.
12. v. To engage (one's self) with another of opposite opinions not to vote on a particular question or class of questions.
13. v. To impair.

WordNet 3.0

1. n. a poker hand with 2 cards of the same value
2. v. bring two objects, ideas, or people together
3. v. engage in sexual intercourse
4. n. two people considered as a unit
5. n. two items of the same kind
6. v. arrange in pairs
7. v. form a pair or pairs
8. v. occur in pairs
9. n. a set of two similar things considered as a unit