An extension at the corner of a fort consisting of two faces and two flanks. It allows the defenders of the fort to cover adjacent bastions and curtains with defensive fire. A demibastion is a small bastion that doesn’t have both faces or both flanks.
A long enclosed passageway, or corridor. Galleries ran along the base of the fort’s walls and were used as defensive positions and as a means to move around the fort without being exposed to fire.
A sloped earthen rampqart that protects the forts vertical walls from cannonfire and prevents surprise attacks. The glacis could also be covered by defensive fire from the parapets and covered way.
A small opening, usually a flared slot, through which small arms may be fired. They also were used to allow light and air to enter into the galleries and as a means to observe enemy movements safely.
Place of Arms:
A protected area, usually near a sally port, in which small groups of men can be assembled when leaving or returning to the fort. Sorties, small patrols, and counter-attacks could be mounted from these areas.
The main slope of the outer walls of the fort. The scarp is often protected from attack by a ditch and other defensive works. The wall on the opposite side of the ditch from the scarp is called the counter scarp.
The level space on the top of the ramparts on which cannons were placed. Defenders of the fort could also fire down on an enemy and use the high position of the terrplein to see approaching ships and armies.