Circumvallation

(-val-lā'shun.) [From L. circum vallo, I surround with a rampart.] (Fortif.) A trench bordered with a rampart, thrown up round the besiegers' camp, or a besieged city. Itis composed of earth dug from the ditch, and is rendered more effective by sharp stakes planted in it; they are otherwise termed lines ofC. They have been seldom employed in modern times. [s. 191]