What is "pair"

Pair \Pair\ (p[^a]r), n. [F. paire, LL. paria, L. paria, pl. of par pair, fr. par, adj., equal. Cf. Apparel, Par equality, Peer an equal.]

1. A number of things resembling one another, or belonging together; a set; as, a pair or flight of stairs. ``A pair of beads.''
   --Chaucer.
   --Beau. & Fl. ``Four pair of stairs.''
   --Macaulay.

   Note: [Now mostly or quite disused.]

   Two crowns in my pocket, two pair of cards.
   --Beau. & Fl.

2. Two things of a kind, similar in form, suited to each other, and intended to be used together; as, a pair of gloves or stockings; a pair of shoes.

3. Two of a sort; a span; a yoke; a couple; a brace; as, a pair of horses; a pair of oxen.

4. A married couple; a man and wife. ``A happy pair.''
   --Dryden. ``The hapless pair.''
   --Milton.

5. A single thing, composed of two pieces fitted to each other and used together; as, a pair of scissors; a pair of pants; a pair of tongs; a pair of bellows.

6. 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; as, there were two pairs on the final vote. [Parliamentary Cant]

   Note: A member who is thus paired with one who would have voted oppositely is said to be paired for or paired against a measure, depending on the member's position.

7. (Kinematics) In a mechanism, two elements, or bodies, which are so applied to each other as to mutually constrain relative motion.

   Note: Pairs are named in accordance with the kind of motion they permit; thus, a journal and its bearing form a turning pair, a cylinder and its piston a sliding pair, a screw and its nut a twisting pair, etc. Any pair in which the constraining contact is along lines or at points only (as a cam and roller acting together), is designated a higher pair; any pair having constraining surfaces which fit each other (as a cylindrical pin and eye, a screw and its nut, etc.), is called a lower pair.

   Pair royal (pl. Pairs Royal) three things of a sort; -- used especially of playing cards in some games, as cribbage; as three kings, three ``eight spots'' etc. Four of a kind are called a double pair royal. ``Something in his face gave me as much pleasure as a pair royal of naturals in my own hand.''
   --Goldsmith. ``That great pair royal of adamantine sisters [the Fates].''
   --Quarles.

   Syn: Pair, Flight, Set.

   Usage: Originally, pair was not confined to two things, but was applied to any number of equal things (pares), that go together. Ben Jonson speaks of a pair (set) of chessmen; also, he and Lord Bacon speak of a pair (pack) of cards. A ``pair of stairs'' is still in popular use, as well as the later expression, ``flight of stairs.''

Pair \Pair\, v. t. [See Impair.] To impair. [Obs.]
--Spenser.

Pair \Pair\, v. i. [imp. & p. p. Paired; p. pr. & vb. n. Pairing.]

1. To be joined in pairs; to couple; to mate, as for breeding.

2. To suit; to fit, as a counterpart.

   My heart was made to fit and pair with thine.
   --Rowe.

3. Same as To pair off. See phrase below.

   To pair off, to separate from a group in pairs or couples; specif. (Parliamentary Cant), to agree with one of the opposite party or opinion to abstain from voting on specified questions or issues. See Pair, n., 6.

Pair \Pair\, v. t.

1. 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.

   Glossy jet is paired with shining white.
   --Pope.

2. To engage (one's self) with another of opposite opinions not to vote on a particular question or class of questions. [Parliamentary Cant]

   Paired fins. (Zo["o]l.) See under Fin.

"to come together with another; be mated or married" (intransitive), also "to make a pair by matching" (transitive), c.1600, from pair (n.). These senses now often are distinguished by pair off (c.1803) for the former and pair up (1908) for the latter. Related: Paired; pairing.

mid-13c., "two of a kind coupled in use," from Old French paire "pair, couple," and directly from Medieval Latin paria "equals," neuter Latin par (genitive paris) "a pair, counterpart, equal," noun use of par (adj.) "equal, equal-sized, well-matched" (see par (n.)). Originally of things. Of persons from late 14c. Meaning "a woman's breasts" is attested from 1922. Pair bond (v.) is first attested 1940, in reference to birds mating.

Etymology 1 n. two similar or identical things taken together; often followed by of. vb. (context transitive English) To group into sets of two. Etymology 2

vb. (context obsolete English) To impair.

1. n. a set of two similar things considered as a unit [syn: brace]

2. two items of the same kind [syn: couple, twosome, twain, brace, span, yoke, couplet, distich, duo, duet, dyad, duad]

3. two people considered as a unit

4. a poker hand with 2 cards of the same value

1. v. form a pair or pairs; "The two old friends paired off" [syn: pair off, partner off, couple]

2. bring two objects, ideas, or people together; "This fact is coupled to the other one"; "Matchmaker, can you match my daughter with a nice young man?"; "The student was paired with a partner for collaboration on the project" [syn: match, mate, couple, twin]

3. occur in pairs [syn: geminate]

4. arrange in pairs; "Pair these numbers" [syn: geminate]

5. make love; "Birds mate in the Spring" [syn: copulate, mate, couple]

PAIR (Peer-Allocated Instant Response) is a project in the Netherlands that aims to match students with best-suited peer candidates for online support. It was launched in 2006 by the Open University of the Netherlands, an online university, and was supported by Fontys University and SURF, the national organization in the Netherlands that coordinates ICT in higher education.

The system works as follows: Online students requiring help type their question into an IM-like client; they are then automatically and instantaneously paired with another student who is currently online. When the conversation is over, both parties rate the experience. The currently used allocation algorithm does not perform a semantic analysis of the question; it allocates peer tutors based on their position in the curriculum relative to the help seeker, their past workload and past ratings.

A simulation of the allocation algorithm was carried out and two 8-week pilot projects were conducted at the Open University and the Fontys University.

In mathematics, a (B, N) pair is a structure on groups of Lie type that allows one to give uniform proofs of many results, instead of giving a large number of case-by-case proofs. Roughly speaking, it shows that all such groups are similar to the general linear group over a field. They were invented by the mathematician Jacques Tits, and are also sometimes known as Tits systems.

In parliamentary practice, pairing is an informal arrangement between the government and opposition parties whereby a member of a House of Parliament agrees or is designated by the party whip to abstain from voting while a member of the other party needs to be absent from the House due to other commitments, illness, travel problems, etc. A pairing would usually be arranged or approved by the party whips and will usually not apply for critical votes, such as no-confidence votes.

The member abstaining from voting is referred to as a pair. In the United States, pairing is an informal arrangement between members and the pairs are called live pairs.

An alternative method of maintaining the relative voting positions of parties in a legislative body is proxy voting, which is used, for example, in New Zealand.

The PAIR (puncture-aspiration-injection-reaspiration) procedure is a noninvasive treatment option to remove hydatid cysts. PAIR is considered an alternative treatment for cystic echinococcosis ( hydatid disease) and is often indicated for patients who do not respond to surgery or benzimidazoles

The PAIR procedure can be performed as follows:

1. ultrasound-guided percutaneous puncture of the cyst
2. aspiration of cystic fluid
3. injection of a scolicidal solution
4. reaspiration of the solution