Warhammer

A warhammer is a hammer wielded for war, rather than construction. Just like the battleaxes, they evolved from the tools and could be used as ones outside the battle. Unlike the battleaxes, warhammers hadn't see much use until the late medieval.

Fullmetal one handed warhammer. A big "Fuck You" towards full plated knights.

Real warhammers have smallish heads on long shafts, designed more like claw hammers or pickaxes, and were used to both hammer unprotected heads and bash and break plate armor to the point where it became useless. To put it simply, they can do maul's and axe's work, and two handed ones can also be used to grapple things like halberds. The blunt side of the warhammer was used mostly as non-lethal weapon, for when you need to capture some aristocrat and later torture some information out of him or sell him to his relatives. The spiked side of warhammer had one of the best armour-piercing capability of it's time, rivaled only by the ridiculously expensive flamberge and ridiculously slow musket (yes, better than arquebuses and pistols). The main downside is that the warhammer's spike usually stuck inside armour after penetration, forcing the user to either spend a few precious seconds to pull it out, or just leave the weapon there. For this reason one-handed warhammers were usually carried by knights and elite troopers as their sidearm, and used only against armored opponents as one-shot weapons. Two-handed warhammers on the other side become "poor man's halberds" - a cheap and effective weapon to make men at arms somewhat not useless against knights.

Fantasy art usually shows them with massive heads the size of anvils and used almost exclusively only for bashing things with blunt end, even if they have the claw. It is obvious that nobody actually used weapons like these because they were too goddamn heavy to swing without throwing your back out.

Warhammer can also refer to one of several games by Games Workshop:

• Warhammer Fantasy Battle (or WHFB) a wargame taking place in a fantasy universe (orcs, elves, dwarves, magic etc)
• Warhammer 40k (W40k or just 40k) another wargame, but this time taking place in a distant future, sci-fi version of the fantasy universe
• Warhammer Fantasy Roleplay (WHFRP) a RPG, based on the Warhammer Fantasy Battles world.
• Warhammer Wednesday The fires from which /tg/ was born.

There is also the Dark Heresy game which is to Warhammer 40k what is WHFRP to WFB (i.e., an RPG set in the W40k universe), but it does not sport Warhammer in the title.