noun.
In fortification: A vault of stone or brickwork, usually built in the thickness of the rampart of a fortress, and pierced in front with embrasures, through which artillery may be fired.
noun.
A shell-proof vault of stone or brick designed to protect troops, ammunition, etc.
noun.
An embrasure.
noun.
The armored bulkhead surrounding guns in iron-clad ships of war, and pierced with portholes through which the guns are run out.
noun.
An erroneous form of casement, .