A medieval [[polearm]] similar to a [[halberd]] or Lucerne hammer, but across the shaft from the hammer, there is a pointy, slightly-hooked spike. This spike was mostly used for hooking an opponent's weapon or limb. The name comes from the French, "bec de corbin," which literally means "crow's beak."

http://en.wikipedia.org/wiki/Bec_de_corbin
crow's beak