CONCAVE, adjective [Latin Hollow. See Cave.] 1. Hollow, and arched or rounded, as the inner surface of a spherical body; opposed to convex; as a concave glass. 2. Hollow, in a general sense; as the concave shores of the Tiber. 3. In botany, a concave leaf is one whose edge stands above the disk. CONCAVE, noun A hollow; an arch, or vault; as the ethereal concave CONCAVE, verb transitive To make hollow.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI