abri, access, adit, aisle, alley, ambulatory, antre, aperture, approach trench, arcade, artery, avenue, bore, bunker, burrow, cave, cavern, channel, cloister, colonnade, communication, communication trench, conduit, connection, corridor, couch, countermine, countersink, coupure, course, cove, covered way, covert, deepen, defile, delve, den, depress, dig, dig out, dike, ditch, dive, double sap, dredge, drill, drive, duct, dugout, earth, egress, entrance, entrenchment, excavate, exit, ferry, fire trench, flying sap, ford, form, fortified tunnel, fosse, foxhole, furrow, gallery, gouge, gouge out, groove, grot, grotto, grub, hole, ingress, inlet, interchange, intersection, junction, lair, lane, lodge, lower, mew, mine, moat, opening, outlet, overpass, parallel, pass, passage, passageway, penetrate, portico, quarry, railroad tunnel, run, sap, scoop, scoop out, scrabble, scrape, scratch, sewer, shaft, shovel, sink, slit trench, spade, subterrane, subway, traject, trajet, trench, trough, troughing, troughway, underpass, warren, way