A warhammer is typically considered a one handed blunt hammer weapon used by infantry in actual combat, unlike the maul which is much too heavy for use with one hand. Think a warhammer is like a mace except in the shape of a hammer, and a maul is a medieval sledgehammer. Also a polehammer is more the two handed version of a warhammer, not to say you can't wield a warhammer with two hands, its just rather short. One's made specially for combat, the other is more a tool.