Source : Webster's Revised Unabridged Dictionary (1913)

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.