Synonyms to opening

abyss, Bassalia, Gehenna, Sheol, Tophet, abysm, abyssal zone, arroyo, bathyal zone, benthos, bottom waters, bottomless depths, box canyon, breach, break, canyon, cavity, chap, chasm, check, chimney, chink, cleft, cleuch, clough, col, coulee, couloir, crack, cranny, crater, crevasse, crevice, cut, cwm, deep, deepness, defile, dell, depth, dig, diggings, dike, ditch, donga, draw, excavation, fault, fissure, flaw, flume, fracture, furrow, gap, gape, gash, gorge, groove, ground, gulch, gulf, gully, hades, hole, hollow, incision, inferno, inner space, joint, kloof, leak, mine, moat, netherworld, notch, nullah, ocean bottom, ocean depths, ocean floor, pass, passage, pelagic zone, perdition, pit, profoundness, profundity, quarry, ravine, rent, rift, rime, rupture, scissure, seam, shaft, slit, slot, split, the deep, the deep sea, the deeps, the depths, trench, underworld, valley, void, wadi, well, workings, yawning abyss, access, Jacksonian epilepsy, Rasputin, Rolandic epilepsy, Svengali, VIP, abdominal epilepsy, accessibility, accession, accretion, accrual, accruement, accumulation, acquired epilepsy, activated epilepsy, addition,