| Main Entry: | |
| Part of Speech: | noun |
| Definition: | hollow in land formation |
| Synonyms: | cave, grotto, hole, pothole, subterrane, subterranean area |
| Notes: | cavern is more vague and rhetorical than cave; a cavern is a large cave |
| Main Entry: | cove |
| Part of Speech: | noun |
| Definition: | inlet, small niche |
| Synonyms: | anchorage, arm, bay, bayou, bight, cave, cavern, creek, estuary, firth, frith, gulf, harbor, hole, lagoon, nook, retreat, slough, sound, wash |
| Main Entry: | crypt |
| Part of Speech: | noun |
| Definition: | burial place |
| Synonyms: | catacomb, cave, cavern, cell, chamber, compartment, grave, grotto, mausoleum, room, sepulcher, tomb, undercroft, vault |
| Main Entry: | grotto |
| Part of Speech: | noun |
| Definition: | cave |
| Synonyms: | antre, cavern, cavity, chamber, den, hollow, rock shelter, subterrane, underground chamber |
| Main Entry: | hole |
| Part of Speech: | noun |
| Definition: | opening in a solid object |
| Synonyms: | aperture, breach, break, burrow, cave, cavern, cavity, chamber, chasm, chink, cistern, cleft, covert, crack, cranny, crater, cut, den, dent, depression, dimple, dip, excavation, eyelet, fissure, foramen, fracture, gap, gash, gorge, hollow, hovel, keyhole, lacuna, lair, leak, mouth, nest, niche, nick, notch, orifice, outlet, passage, peephole, perforation, pit, pocket, pockmark, puncture, rent, retreat, scoop, shaft, shelter, space, split, tear, tunnel, vacuity, vent, void, window |
| Antonyms: | closure, solid |
| Main Entry: | hollow |
| Part of Speech: | noun |
| Definition: | empty or dented area |
| Synonyms: | basin, bottom, bowl, cave, cavern, cavity, chamber, channel, cleft, concavity, crater, cup, dale, den, depression, dimple, dip, dish, excavation, groove, gulf, hole, indentation, notch, pit, pocket, sag, scoop, sinkage, sinkhole, socket, trough, vacuity, valley, void |
| Antonyms: | solid |
| Main Entry: | vault |
| Part of Speech: | noun |
| Definition: | depository |
| Synonyms: | basement, box, can, catacomb, cavern, cellar, crib*, crypt, dungeon, grave, mausoleum, pit, repository, safe, safe-deposit box, sepulcher, strong room, tomb |