The Collaborative International Dictionary of English v.0.48:

Buckshot \Buck"shot`\, n.
   A coarse leaden shot, larger than swan shot, used in hunting
   deer and large game.
   [1913 Webster]

WordNet (r) 3.0 (2006):

buckshot
    n 1: small lead shot for shotgun shells [syn: bird shot,
         buckshot, duck shot]