Source : Webster's Revised Unabridged Dictionary (1913)

Haunch \Haunch\ (?; 277), n. [F. hanche, of German origin; cf.
   OD. hancke, hencke, and also OHG. ancha; prob. not akin to E.
   ankle.]
   1. The hip; the projecting region of the lateral parts of the
      pelvis and the hip joint; the hind part.

   2. Of meats: The leg and loin taken together; as, a haunch of
      venison.

   {Haunch bone}. See {Innominate bone}, under {Innominate}.

   {Haunches of an arch} (Arch.), the parts on each side of the
      crown of an arch. (See {Crown}, n., 11.) Each haunch may
      be considered as from one half to two thirds of the half
      arch.

Source : WordNet®

haunch
     n 1: the hip and buttock and upper thigh in human beings
     2: the loin and leg of a quadruped