The Collaborative International Dictionary of English v.0.48:
Chamfron \Cham"fron\, n. [F. chanfrein.] (Anc. Armor) The frontlet, or head armor, of a horse. [Written also champfrain and chamfrain.] [1913 Webster]WordNet (r) 3.0 (2006):
chamfron n 1: medieval plate armor to protect a horse's head [syn: chanfron, chamfron, testiere, frontstall, front- stall]