Advanced work: any work of fortification located outside the glacis, yet within musketry range.
Angle of defense: the angle formed by a line of defense and a flank.
Banquette*: a continuous step or ledge at the base of a parapet, on which defenders stood to fire over the top of the wall.
Bastion*: a projection in the enceinte, comprised of two faces and two flanks, which enabled the garrison to defend the ground adjacent to the enceinte.
Bombproof: a structure designed to provide security against artillery fire.
Branch gallery: a small tunnel dug from a listening gallery to intercept enemy miners.
Breast height: a wall, chest high, from behind which musketry fire could be directed against an approaching army.
Capital of the bastion: an imaginary line connecting the point of the bastion and the point of the corresponding angle of the polygon of fortification.
Caponnier: a passage across a dry ditch, formed by two parapets which sloped down to the level of the ditch. Generally there was a banquette on each side of the passage from which the ditch could be defended. The term also denotes an architectural form extending from the main body of the place for the purpose of providing for flanking fire.
Casemate*: a bombproof enclosure, generally located under the rampart and terreplein, for the purpose of housing cannon which fired through embrasures in the scarp. Casemates were also used as quarters, magazines, etc. In permanent fortifications they were vaulted, but in impermanent works they sometimes had trabeated structures.
Cavalier: in fortification, a raised work where artillery was placed to command the surrounding works or country. It was commonly placed on the terreplein of a bastion or curtain.
Coping: the top course of a parade face wall revetment.
Cordon*: the top course of the scarp, normally designed to protect the wall from weathering. In plan, the line created by the cordon was termed the “magistral line.”
Counterfire room: see counterscarp gallery.
Counterfort: interior buttress, used to strengthen revetment walls.
Countermine gallery: underground tunnel excavated by defenders for the purpose of intercepting the mines of besieging forces and destroying their works. From these listening galleries could be excavated.
Counterscarp*: the exterior side of the ditch—the side of the ditch away from the body of the place.
Counterscarp gallery: a work located behind the counterscarp, from which the ditch could be defended with reverse fire.
Covered way*: a road around a fortification between the ditch and the glacis. It was protected from enemy fire by a parapet, at the foot of which was generally a banquette enabling the coverage of the glacis with musketry. In addition to its function as an outer line of defense, it served as a place for sorties to assemble.
Coverface: a work comprised of two faces forming a salient angle, placed before bastions or ravelins, but separated from them, to protect their faces from cannon missiles.
Crenated gallery: See reverse fire gallery
Crotchet: (technically, crotchet du glasis): a passage around traverse on the covered way.
Curtain*: a section of a bastioned fortification that lies between two bastions.
Curtain angle: in plan, the angle formed between the curtain and the flank.
Deblais: earth or stone excavated from the ditch to form the ramparts, terreplein, etc.
Defilade (defilement): the arrangement of fortifications to minimize the effect of plunging cannon fire from a nearby eminence.
Demi-bastion: a bastion with only one face and one flank.
Demi-gorge: a segment lying on the prolongation of the line of the curtain and defined by the point of the curtain angle and the intersection of the line of the curtain with the capital of the bastion.
Detached work: in general, a work beyond the range of musketry from the body of the place, yet functionally related to its defense.
Ditch*: a wide, deep trench around a defensive work. When filled with water, it was termed a “wet ditch,” otherwise it was called a “dry ditch.”
Drawbridge: a bridge across a deep ditch which may be raised to isolate the body of the place from the covered way or other approach.