or CAZEMATE, in fortification, a kind of vault or arch of stone-work, in that part of the flank of a bastion next the curtain; serving as a battery to defend the face of the opposite bastion, and the moat or ditch.

It is now seldom used, because the batteries of the enemy are apt to bury the artillery of the casemate in the ruins of the vault; besides, the great smoke made by the discharge of the cannon renders it intolerable to the men. So that, instead of the ancient covered casemates, later engineers have contrived open ones, only guarded by a parapet, &c.

Casemate is also used for a well with several subterraneous branches, dug in the passage of the bastion, till the miner is heard at work, and air given to the mine.