Concave

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.

A hollow; an arched vault; a cavity; a recess.

A curved sheath or breasting for a revolving cylinder or roll.

To make hollow or concave.