abysm, abyss, alveolation, alveolus, antrum, armpit, basin, birthmark, blackhead, bleb, blemish, blister, bowl, bulla, cavity, chasm, check, cicatrix, comedo, concave, concavity, crack, craze, crevasse, crypt, cup, deep, defacement, defect, deformation, deformity, depression, depth, dip, disfiguration, disfigurement, distortion, fault, flaw, fold, follicle, freckle, funnel chest, gulf, hemangioma, hickey, hole, hollow, hollow shell, keloid, kink, lacuna, lentigo, milium, mole, needle scar, nevus, pimple, pit, pock, pocket, pockmark, port-wine mark, port-wine stain, punch bowl, pustule, rift, scab, scar, scoop, scratch, sebaceous cyst, shaft, shell, sink, sinus, socket, split, strawberry mark, sty, track, trough, twist, verruca, vesicle, vug, wale, warp, wart, weal, well, welt, wen, whitehead, yawning abyss
depth, deepness, profundity, depression, hollow, pit, shaft, well, crater
, gulf, bowels of the earth, botttomless pit, hell, soundings, depth of water, water, draught, submersion, plummet, sound, probe, sounding rod, sounding line, lead, bathymetry, sonar, side-looking sonar, bathometer, deep, deep seated, profound, sunk, buried, submerged, subaqueous, submarine, subterranean, subterraneous, subterrene, underground, bottomless, soundless, fathomless, unfathomed, unfathomable, abysmal, deep as a well, bathycolpian, benthal, benthopelagic, downreaching, yawning, knee deep, ankle deep, beyond one's depth, out of one's depth, over head and ears, mark twine, mark twain.
concavity, depression, dip, hollow, hollowness, indentation, intaglio, cavity, dent, dint, dimple, follicle, pit, sinus, alveolus, lacuna, excavation, strip mine, trough, honeycomb, cup, basin, crater
, punch bowl, cell, socket, valley, vale, dale, dell, dingle, combe, bottom, slade, strath, glade, grove, glen, cave, cavern, cove, grot, grotto, alcove, cul-de- sac, gully, arch, bay, excavator, sapper, miner, honeycomb (sponge), depressed, alveolate, calathiform, cup-shaped, dishing, favaginous, faveolate, favose, scyphiform, scyphose, concave, hollow, stove in, retiring, retreating, cavernous, porous, infundibul, infundibular, infundibuliform, funnel shaped, bell shaped, campaniform, capsular, vaulted, arched.