THESAURUS
Tunnel
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
ROGET THESAURUS
Tunnel
Method
N
method, way, manner, wise, gait, form, mode, fashion, tone, guise, modus operandi, MO, procedure, path, road, route, course, line of way, line of road, trajectory, orbit, track, beat, tack, steps, stair, staircase, flight of stairs, ladder, stile, perron, bridge, footbridge, viaduct, pontoon, steppingstone, plank, gangway, drawbridge, pass, ford, ferry, tunnel, pipe, door, gateway, channel, passage, avenue, means of access, approach, adit, artery, lane, loan, alley, aisle, lobby, corridor, back-door, back-stairs, secret passage, covert way, vennel, roadway, pathway, stairway, express, thoroughfare, highway, turnpike, freeway, royal road, coach road, broad highway, King's highway, Queen's highway, beaten track, beaten path, horse road, bridle road, bridle track, bridle path, walk, trottoir, footpath, pavement, flags, sidewalk, crossroad, byroad, bypath, byway, cut, short cut carrefour, private road, occupation road, highways and byways, railroad, railway, tram road, tramway, towpath, causeway, canal, street, speedway, adv, how, in what way, in what manner, by what mode, so, in this way, after this fashion, one way or another, anyhow, somehow or other, by way of, via, in transitu, on the high road to, hae tibi erunt artes.
Concavity
VB
be concave, retire, cave in, render concave, depress, hollow, scoop, scoop out, gouge, gouge out, dig, delve, excavate, dent, dint, mine, sap, undermine, burrow, tunnel, stave in.
Opening
N
opening, hole, foramen, puncture, perforation, fontanel, transforation, pinhole, keyhole, loophole, porthole, peephole, mousehole, pigeonhole, eye of a needle, eyelet, slot, opening, aperture, apertness, hiation, yawning, oscitancy, dehiscence, patefaction, pandiculation, chasm, embrasure, window, casement, abatjour, light, sky light, fan light, lattice, bay window, bow window, oriel, dormer, lantern, outlet, inlet, vent, vomitory, embouchure, orifice, mouth, sucker, muzzle, throat, gullet, weasand, wizen, nozzle, placket, portal, porch, gate, ostiary, postern, wicket, trapdoor, hatch, door, arcade, cellarway, driveway, gateway, doorway, hatchway, gangway, lich gate, way, path, thoroughfare, channel, passage, passageway, tube, pipe, water pipe, air pipe, vessel, tubule, canal, gut, fistula, adjutage, ajutage, ostium, smokestack, chimney, flue, tap, funnel, gully, tunnel, main, mine, pit, adit, shaft, gallery, alley, aisle, glade, vista, bore, caliber, pore, blind orifice, fulgurite, thundertube, porousness, porosity, sieve, cullender, colander, cribble, riddle, screen, honeycomb, apertion, perforation, piercing, terebration, empalement, pertusion, puncture, acupuncture, penetration, key, opener, master key, password, combination, passe- partout, open, perforated, perforate, wide open, ajar, unclosed, unstopped, oscitant, gaping, yawning, patent, tubular, cannular, fistulous, pervious, permeable, foraminous, vesicular, vasicular, porous, follicular, cribriform, honeycombed, infundibular, riddled, tubulous, tubulated, piped, tubate, opening, aperient, Int, open sesame!.
VB
open, ope, gape, yawn, bilge, fly open, perforate, pierce, empierce, tap, bore, drill, mine, tunnel, transpierce, transfix, enfilade, impale, spike, spear, gore, spit, stab, pink, puncture, lance, stick, prick, riddle, punch, stave in, cut a passage through, make way for, make room for, uncover, unclose, unrip, lay open, cut open, rip open, throw open, pop open, blow open, pry open, tear open, pull open.
Conduit
N
conduit, channel, duct, watercourse, race, head race, tail race, abito, aboideau, aboiteau, bito, acequia, acequiador, acequiamadre, arroyo, adit, aqueduct, canal, trough, gutter, pantile, flume, ingate, runner, lock-weir, tedge, vena, dike, main, gully, moat, ditch, drain, sewer, culvert, cloaca, sough, kennel, siphon, piscina, pipe, funnel, tunnel, water pipe, waste pipe, emunctory, gully hole, artery, aorta, pore, spout, scupper, adjutage, ajutage, hose, gargoyle, gurgoyle, penstock, weir, flood gate, water gate, sluice, lock, valve, rose, waterworks, pipeline, vascular.