A bec de corbin is a type of pole weapon that was popular in medieval Europe. The name is French for 'crow's beak' literally. As a warhammer it bore striking resemblances to the Lucerne hammer, consisting of a modified hammers head and spike mounted atop a long pole. Unlike the Lucerne hammer, the bec de corbin was used primarily with the 'beak' or fluke to attack instead of the hammer head. The hammer face balancing the beak was often blunt instead of the multi pronged Lucerne, and the beak tended to be stouter; better designed for tearing armor. Also the spike mounted on the top of head was not nearly as long and thin as in the Lucerne. Bec de Corbin occasionally becomes a catch all for any type of warhammer, such as a maul or a horseman's pick.
A similar name bec de faucon (meaning 'falcon's beak') reffers to a related weapon called a pollaxe or more specifically the hook on its reverse side.
Becde Faucon - a polearm with a large hammer head instead of an axe, and backed with a spike or curved fluke.
The second form, usually referred to as the "Becde Faucon" sported a large hammer head instead of an axe, and was backed with a spike or curved fluke.
Thalhoffer and De Liberi both provide many instructional plates on the use of the hache, but the most important document is the anonymous "Le Jeu de la Hache," of the mid-15th century, and translated into modern English by Dr. Sydney Anglo.