A thick, very hard, salted wheatflour biscuit baked so as to remove almost all water. Usually soaked in water or broth to eat. Also known as 'sea-biscuit' or 'ship's biscuit' or 'hard bread'.

Inexpensive and imperishable, hardtak was long a staple for sea voyages and military campaigns. At the time of the Armada in 1588, the daily allowance on board ship was 1lb of biscuit plus 1 gallon of beer and hardtack is still an item in some military ration packs. The fact that the biscuits could be stored away for emergency use means that very old examples are often found, and generally just as edible after a couple of centuries as they were when fresh.