(Weapon) An advance on the club, a mace is a wooden, metal-reinforced or metal shaft, 3 or more feet (a meter or more) long, with a head made of iron or steel adding another foot to 18 inches (30 to 45 cm) to the length of the weapon. The head is normally about or slightly thicker than the diameter of the shaft, shaped with flanges, knobs or spikes to allow greater penetration of armour. It, like the war hammer and various other weapons of the time, came about because of the increased use of more effective armour on the battlefield.
A variety of mace called the morning star had its spiked metal ball suspended from a chain attached to the handle, rather than being directly mounted.
Medieval bishops carried maces in battle (Odo of Bayeux appears on the Bayeux tapestry wielding one) instead of swords, so as to conform to the canonical rule which forbade priests to shed blood.
(Symbol) A ceremonial mace can represent authority and prestige, as in the House of Commons in a Westminster System parliament. Processions often feature such maces: either on parliamentary or in formal university occasions. The ecclesiatical equivalent of the mace-bearer, the dodsman, appears in church contexts.
Mace is also a brand of tear gas, often used by police.