THESAURUS
Concave
arched, arciform, arclike, arcual, bandy, boat-shaped, boatlike, bowed, bowl-shaped, bowlike, bowllike, cavelike, cavernous, concaved, convex, craterlike, cup-shaped, cupped, cymbiform, dish-shaped, dished, dishing, dishlike, embowed, funnel-breasted, funnel-chested, funnel-shaped, gibbose, gibbous, hollow, hollowed, humpbacked, humped, humpy, hunched, hunchy, incurved, incurving, incurvous, infundibular, infundibuliform, navicular, naviform, oxbow, retiring, retreating, saucer-shaped, scaphoid, scyphate, spoonlike, sunk, sunken, vaulted
ROGET THESAURUS
Concave
Concavity
N
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.