Source : Webster's Revised Unabridged Dictionary (1913)

Gunstock \Gun"stock`\, n.
   The stock or wood to which the barrel of a hand gun is
   fastened.

Source : WordNet®

gunstock
     n : the handle of a handgun or the butt end of a rifle or
         shotgun or part of the support of a machine gun or
         artillery gun; "the rifle had been fitted with a special
         stock" [syn: {stock}]