concave shape(n = noun.shape) concavity, incurvation, incurvature - a shape that curves or bends inward;
is a kind of solid
has particulars: dome, fossa, pit, corner, niche, recess, recession, bowl, trough, pocket, scoop, depression, impression, imprint, cup, indentation, indenture

amorphous shape, angular shape, bell shape, change of shape, change shape, concave, concave lens, concave polygon, concave polyhedron, cone shape, convex shape, curved shape, disk shape, distorted shape, funnel shape, gaussian shape, good shape, in shape, leaf shape, natural shape, out of shape, polygonal shape, poor shape, round shape, shape, shape constancy, shape up, structural shape, take shape, top shape, wave shape, wedge shape