Embrasure

Embrasure, a term employed in fortification to denote an opening in a wall or embattlement through which a gun may be trained, or the space in a wall sloping laterally towards a window. In the case of the embrasure for a gun the narrow part is inward, the sides sloping outward to admit a wider lateral range for pointing a gun, in the case of a window the wider part is towards the interior. An embrasure may be either direct, i.e. at right angles to the side of the wall through which it is pierced, or oblique, i.e. at an acute angle with such side.