| Main Entry: | |
| Part of Speech: | adjective |
| Definition: | depressed, hollowed; submerged |
| Synonyms: | buried, caved-in, concave, fallen-in, immersed, indented, recessed |
| Main Entry: | concave |
| Part of Speech: | adjective |
| Definition: | curved, depressed |
| Synonyms: | biconcave, cupped, dented, dimpled, dipped, excavated, hollow, hollowed, incurvate, incurvated, incurved, indented, round, rounded, sagging, scooped, sinking, sunken |
| Notes: | convex (from Latin convexus 'arched, vaulted') refers to a surface that curves outward, concave (from Latin concavus 'hollow') to a surface that curves inward |
| Antonyms: | convex, distended |
| Main Entry: | depressed |
| Part of Speech: | adjective |
| Definition: | concave, pushed down |
| Synonyms: | hollow, indented, recessed, set back, sunken |
| Antonyms: | bulging, convex, pushed up, raised |
| Main Entry: | hollow |
| Part of Speech: | adjective |
| Definition: | empty, hollowed out |
| Synonyms: | alveolate, arched, carved out, cavernous, cleft, concave, cup-shaped, cupped, curved, deep-set, depressed, dimpled, excavated, incurved, indented, infundibular, not solid, notched, pitted, striated, sunken, troughlike, unfilled, vacant, vaulted, void |
| Antonyms: | convex, full, raised, solid |
| Main Entry: | low |
| Part of Speech: | adjective |
| Definition: | close to the ground; short |
| Synonyms: | below, beneath, bottom, bottommost, crouched, decumbent, deep, depressed, flat, ground-level, inferior, junior, lesser, level, little, low-hanging, low-lying, low-set, lowering, minor, nether, not high, profound, prostrate, rock-bottom, shallow, small, squat, squatty, stunted, subjacent, subsided, sunken, under, unelevated |
| Antonyms: | above, high, tall |
| Main Entry: | subterranean |
| Part of Speech: | adjective |
| Definition: | hidden, underground |
| Synonyms: | below ground, buried, covered, covert, hush-hush, on the QT, private, secret, subterrestrial, subversive, sunken, under wraps, underfoot |
| Main Entry: | underground |
| Part of Speech: | adjective |
| Definition: | below the surface |
| Synonyms: | below ground, buried, covered, in the recesses, subterranean, subterrestrial, sunken, underfoot |
| Antonyms: | aboveground, ground, sky |
| Main Entry: | underwater |
| Part of Speech: | adjective |
| Definition: | under the water's surface |
| Synonyms: | immersed, subaquatic, subaqueous, submarine, submerged, sunken, undersea |
| Main Entry: | hypogeal |
| Part of Speech: | adjective |
| Definition: | underground |
| Synonyms: | below ground, buried, covered, hypogean, hypogeous, in the recesses, subterranean, subterrestrial, sunken, underfoot |