gorge

A gorge in field fortification is the "unexposed side of a fieldwork", typically the rear of an independent fieldwork or detached outwork in front of the main fortress or defensive position. Outworks with open gorges Straith describes three commonly used classes of field work: "works open at the gorge, works enclosed all round and lines." He lists the following as works open at the gorge: Redan Lunette Redan with flanks Double Redan Tenaille-head Bastion-head Closed works are the redoubt, star fort and bastioned fort.