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.

Source: Webster's Revised Unabridged Dictionary (1913)