(in fortification) an opening, as a loophole or crenel, through which missiles may be discharged.
2.
Architecture. a splayed enlargement of a door or window toward the inner face of a wall.
3.
Dentistry. the space between adjacent teeth.
Origin: 1695–1705; < F, equiv. to embras(er) to enlarge a window or door opening, make an embrasure (appar. the same v. as embraser to set on fire (see embrace2), though sense shift unclear) + -ure-ure
An opening in a thick wall for a door or window, especially one with sides angled so that the opening is larger on the inside of the wall than on the outside.
A flared opening for a gun in a wall or parapet.
[French, from embraser, to widen an opening.] em·bra'sured adj.
1702, from Fr. embrasure, from O.Fr. embraser "to cut at a slant, make a groove or furrow in a door or window," from en- "in" + braser "to cut at a slant."