A ditch in military engineering is an obstacle, designed to slow down or break up an attacking force, while a trench is intended to provide cover to the defenders. In medieval fortification, a ditch was constructed in front of a defensive wall to hinder mining. When filled with water, such a defensive ditch is called a moat, however, moats may also be dry. Today ditches are obsolescent as an obstacle, but are still often used as anti-vehicle obstacles. A fence concealed in a ditch is called a ha-ha, scarp, the inner side of the ditch is called the scarp slope. This may be revetted with masonry or brickwork, in which case, cordon, a course of protruding masonry along the top of a scarp wall, intended to make it harder for an enemy to stand a ladder against it. Rampart, the wall of the fort which can be made of earth or masonry, is topped by a parapet for the defenders to fire over. Berm, a ledge between the wall and the exterior slope of the rampart, designed to increase the stability of the rampart. Faussebraye, a parapet between the rampart and the inner edge of the ditch. Carnot wall, a wall between the rampart and the inner edge of the ditch. Chemin de ronde, a pathway running along the berm, behind the faussebraye or Carnot wall, cunette, a narrow channel that runs along the floor of the ditch for drainage purposes. Bartardeau, a type of dam across a ditch that is part wet. Counterscarp, the slope or wall of the ditch. Sally port, a door allowing the defenders to enter the ditch should it be occupied by the enemy. Caponier, a masonry or brick structure extending into the ditch or traversing across it, it is pierced with loopholes to enable the defenders to fire along the floor of the ditch. Counterscarp gallery, a passage constructed behind the wall and pierced with loopholes. Glacis, an earth slope angled away from the ditch, the height and angle of the glacis was calculated to protect the rampart from direct fire but to allow the defenders to fire over it. Place-of-arms, an area of the covered way at an angle of the ditch
Ditch of Valletta, which was built between 1566 and the 1570s.
A section through the ditch and rampart of a typical early modern artillery fortification (16th to 19th centuries). The elements are: a) glacis, b) banquette, c) covered way or covertway d) counterscarp, e) ditch (dry), f) cunette, g) scarp or escarp, h) faussebraye, i) chemin de ronde, j) rampart (exterior slope), k) parapet, m) terreplein.