- concave shape, concavity, incurvation, incurvature - a shape that curves or bends inward
--1 is a kind of solid
--1 has particulars:dome; pit, fossa; recess, recession, niche, corner; bowl, trough; scoop, pocket; depression, impression, imprint; cup; indentation, indenture - concavity, concaveness - the property possessed by a concave shape
--2 is a kind of shape, form, configuration, contour, conformation
--2 has particulars: hollowness