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.]

The Collaborative International Dictionary of English v.0.48:

Crotch \Crotch\, v. t. [imp. & p. p. Crotched (kr[o^]cht); p.
   pr. & vb. n. Crotch"ing.]
   1. To provide with a crotch; to give the form of a crotch to;
      as, to crotch the ends of ropes in splicing or tying
      knots.
      [Webster 1913 Suppl.]

   2. (Logging) To notch (a log) on opposite sides to provide a
      grip for the dogs in hauling. [Western, U. S.]
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

crotch
    n 1: the region of the angle formed by the junction of two
         branches; "they took the south fork"; "he climbed into the
         crotch of a tree" [syn: fork, crotch]
    2: the angle formed by the inner sides of the legs where they
       join the human trunk [syn: crotch, fork]
    3: external sex organ [syn: genitalia, genital organ,
       genitals, private parts, privates, crotch]