Gabion

Gabion (Ital. gabbia, related to Lat. cavea, 'hollow'), a hollow cylinder of basket-work, 3 feet high and 2 in diameter, employed in fortification for revetting purposes—i.e. to retain earth at a steep slope. A sap-roller consists of two concentric gabions, one 4 feet, the other 2 feet 8 inches in diameter, the space between being wedged full of pickets of hard wood, so as to form a movable protection for the men working at a saphead. See MINES.