The Collaborative International Dictionary of English v.0.48:

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.
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   2. To suit; to fit, as a counterpart.
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            My heart was made to fit and pair with thine.
                                                  --Rowe.
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   3. Same as To pair off. See phrase below.
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   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.
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