Synonyms and related words :
abri, abysm, abyss, approach trench, aqueduct, arch dam, arroyo, backstop, bamboo curtain, bank, bar, barrage, barrier, bear-trap dam, beaver dam, boom, box canyon, breach, break, breakwater, breastwork, brick wall, buffer, bulkhead, bulwark, bunker, canal, canalization, canyon, cavity, channel, chap, chasm, check, chimney, chink, cleft, cleuch, clough, cofferdam, col, communication trench, coulee, couloir, countermine, coupure, crack, cranny, crevasse, crevice, crimp, cut, cwm, dam, defense, defile, dell, dike, ditch, donga, double sap, draw, dugout, earthwork, embankment, entrenchment, excavation, fault, fence, fire trench, fissure, flaw, flume, flying sap, fortified tunnel, fosse, foxhole, fracture, furrow, gallery, gap, gape, gash, gate, goffer, gorge, gravity dam, groin, groove, gulch, gulf, gully, gutter, ha-ha, hole, hydraulic-fill dam, incision, iron curtain, jam, jetty, joint, kennel, kloof, leak, leaping weir, levee, logjam, milldam, mine, mole, mound, notch, nullah, opening, parallel, parapet, pass, passage, pleat, portcullis, rampart, ravine, rent, rift, rime, roadblock, rock-fill dam, rupture, sap, scissure, seam, seawall, shutter dam, slit, slit trench, slot, split, stone wall, sunk fence, trench, trough, tunnel, valley, void, wadi, wall, weir, wicket dam, work