6. 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; as, there were two pairs on the final vote. [Parliamentary Cant]
7. (Kinematics)
Defn: 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. [Written corruptly parial and prial.]
Syn. — Pair, Flight, Set. 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. i. [imp. & p. p. Paired; p. pr. & vb. n. Pairing.]
1. To be joined in paris; 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 company 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.