The Collaborative International Dictionary of English v.0.48:

Halve \Hal"ve\ (h[aum]l"ve), n.
   A half. [Obs.] --Chaucer.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Halve \Halve\ (h[aum]v), v. t. [imp. & p. p. Halved
   (h[aum]vd); p. pr. & vb. n. Halving.] [From Half.]
   1. To divide into two equal parts; as, to halve an apple; to
      be or form half of.
      [1913 Webster]

            So far apart their lives are thrown
            From the twin soul that halves their own. --M.
                                                  Arnold.
      [1913 Webster]

   2. (Arch.) To join, as two pieces of timber, by cutting away
      each for half its thickness at the joining place, and
      fitting together.
      [1913 Webster]

   3. Of a hole, match, etc., to reach or play in the same
      number of strokes as an opponent.

WordNet (r) 3.0 (2006):

halve
    v 1: divide by two; divide into halves; "Halve the cake"