1. (n.) The act of surrounding with a wall or rampart.

2. (n.) A line of field works made around a besieged place and the besieging army, to protect the camp of the besiegers against the attack of an enemy from without.

advanced work balistraria bank banquette barbed-wire entanglement barbican barricade barrier bartizan bastion battlement breastwork bulwark casemate cheval-de-frise circumvallation contravallation counterscarp curtain demibastion dike drawbridge earthwork enclosure entanglement escarp escarpment fence fieldwork fortalice fortification glacis loophole lunette machicolation mantelet merlon mound outwork palisade parados parapet portcullis postern gate rampart ravelin redan redoubt sally port scarp sconce stockade tenaille vallation vallum work