1. A splay of a door or window. Apart, in the twilight gloom of a windows embrasure, sat the lovers. (Longfellow)
2. An aperture with slant sides in a wall or parapet, through which cannon are pointed and discharged; a crenelle.
Origin: f, fr. Embraser, perh. Equiv. To ebraser to widen an opening; of unknown origin.