adj. Hollow and curved or rounded; vaulted; - said of the interior of a curved surface or line, as of the curve of the of the inner surface of an eggshell, in opposition to convex; as, a concave mirror; the concave arch of the sky. Hollow; void of contents.
- n. A hollow; an arched vault; a cavity; a recess. (Mech.) A curved sheath or breasting for a revolving cylinder or roll.
- vb. To make hollow or concave.