Circumvallation, Lines Of
CIRCUMVALLATION, LINES OF (from Lat. circum, round, and vallum, a rampart), in fortification, a continuous circle of entrenchments surrounding a besieged place. "Lines of Contravallation" were similar works by which the besieger protected himself against the attack of a relieving army from any quarter. These continuous lines of circumvallation and contravallation were used only in the days of small armies and small fortresses, and both terms are now obsolete.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)