Combatants, soldiers whose duty it is to fight both in attack and defence, are either cavalry, artillery, engineers, or infantry. Non-combatants, on the other hand, perform administrative duties, and fight only in self-defence, though soldiers and armed, as in the commissariat, transport, ordnance store, medical, pay, and veterinary departments. See FRANC-TIREURS.
In the navy, all seamen are combatants, but engineers, doctors, paymasters, and chaplains are non-combatants.