from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Curved like the inner surface of a sphere.
- n. A concave surface, structure, or line.
- transitive v. To make concave.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. curved like the inner surface of a sphere or bowl
- n. A concave surface or curve.
- n. The vault of the sky.
- n. One of the celestial spheres of the Ptolemaic or geocentric model of the world.
- n. An element of a curved grid used to separate desirable material from tailings or chaff in mining and harvesting.
- n. An indentation running along the base of a surfboard, intended to increase lift.
- n. An indented area on the top of a skateboard, providing a position for foot placement and increasing board strength.
- v. To render concave, or increase the degree of concavity.
from the GNU version of the Collaborative International Dictionary of English
- 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
- adj. Hollow; void of contents.
- n. A hollow; an arched vault; a cavity; a recess.
- n. A curved sheath or breasting for a revolving cylinder or roll.
- transitive v. To make hollow or concave.
from The Century Dictionary and Cyclopedia
- Curved or rounded in the manner of the circumference of a circle or the surface of a sphere when viewed from the center; presenting a hollow or incurvation; incurved; hence, bounded by such a line or surface: as, a concave mirror.
- Hollow; empty.
- n. A hollow; an arch or vault; a concavity.
- n. Any inwardly curved portion of a machine: as, the concave of a thresher (the curved breast in which the cylinder works).
- n. A concave mirror.
- To make hollow.
- n. The vault or arch of heaven: as, “the blue concave.”
- n. A playing card so trimmed that it can be separated from others according to the purpose for which the pack was prepared.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. curving inward
Middle English, from Latin concavus : com-, intensive pref.; see com- + cavus, hollow.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin concavus. (Wiktionary)