Coffer

in fortification, a hollow lodgment sunk in the bottom of a dry ditch, from 6 to 7 feet deep, and from 16 to 18 feet broad, and the length of it, the whole breadth of the said ditch, from side to side. The besieged generally make use of these coffers to repulse the besiegers, when they attempt to pa the ditch: they are distinguished only by their length from Caponiers; the difference between coffers and the traverse and gallery, consists in this, that the latter are made by the besiegers, and the former by the besieged. They are covered with joists, hurdles, and earth, raised 2 feet above the bottom of the ditch; which rising serves instead of a parapet, with loop-holes in it.