The Collaborative International Dictionary of English v.0.48:

Crotch \Crotch\ (kr[o^]ch; 224), n.; pl. Crotches
   (kr[o^]ch"[e^]z). [Cf. Crotchet, Crutch.]
   1. The angle formed by the parting of two legs or branches; a
      fork; the point where a trunk divides; as, the crotch of a
      tree. more specifically, the space on the human torso
      between the two legs; also, the corresponding part between
      the legs of a pair of pants, which is in contact with the
      crotch of the wearer; as, pants with a tight crotch have
      become very popular.
      [1913 Webster +PJC]

   2. (Naut.) A stanchion or post of wood or iron, with two arms
      for supporting a boom, spare yards, etc.; -- called also
      crane and crutch. --Totten.
      [1913 Webster]

   3. (Billiards) In the three-ball carom game, a small space at
      each corner of the table. See Crotched, below.
      [Webster 1913 Suppl.]