concave

adjective

1. curving inward

Similar word(s): acetabular, cotyloid, cotyloidal, biconcave, bursiform, pouchlike, saclike, cuplike, cupular, cupulate, dished, patelliform, planoconcave, recessed, umbilicate, intrusive

noun

1. A concave surface or curve.

2. The vault of the sky.

3. One of the celestial spheres of the Ptolemaic or geocentric model of the world.

- Aristotle makes [Fire] to move to the concave of the Moon. - Thomas Salusbury (1661).

4. (manufacturing) An element of a curved grid used to separate desirable material from tailings or chaff in mining and harvesting.

5. (surfing) An indentation running along the base of a surfboard, intended to increase lift.

6. (skateboarding) An indented area on the top of a skateboard, providing a position for foot placement and increasing board strength.

verb

1. To render concave, or increase the degree of concavity.