embrasure

thumb|Embrasure with three angles of fire, Keoti Fort, India thumb|upright|A loophole or inverted keyhole embrasure, allowing both arrow fire (through the arrowslit at the top) and small cannon fire through the circular openings, [[Fort-la-Latte, France]] thumb|Embrasure of Chinese wall thumb|Embrasures at Fortifications of Mdina|Mdina, [[Malta]] thumb|upright|Embrasure at Atalaya Castle (Spain)|Atalaya Castle, Spain

An embrasure (or crenel or crenelle; sometimes called gunhole in the domain of gunpowder-era architecture) is the opening in a battlement between two raised solid portions (merlons). Alternatively, an embrasure can be a space hollowed out throughout the thickness of a wall by the establishment of a bay. This term designates the internal part of this space, relative to the closing device, door or window. In fortification this refers to the outward splay of a window or of an arrowslit on the inside.