Etymology From Middle English concave, from Old French concave, from Latin concavus.
1
Curved like the inner surface of a sphere or bowl.
2
Geometry, Mathematics, SciencesOf a polygon Not convex; having at least one internal angle greater than 180 degrees.
3
Satisfying the property that all segments connecting two points on the function's graph lie below the function.
Functional analysis Of a real-valued function on the reals
4
Hollow; empty.
as concave […] as a worm-eaten nutc. 1598–1600 (date written), William Shakespeare, “As You Like It”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act III, scene iv]:
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
Business, Manufacturing An element of a curved grid used to separate desirable material from tailings or chaff in mining and harvesting.
5
Hobbies, Lifestyle, Sports, Surfing An indentation running along the base of a surfboard, intended to increase lift.
6
Hobbies, Lifestyle, Skateboarding, Sports An indented area on the top of a skateboard, providing a position for foot placement and increasing board strength.
7
Gambling, Games A playing card made concave for use in cheating.
concave
verb
Etymology From Middle English concave, from Old French concave, from Latin concavus.
1
To render concave, or increase the degree of concavity.