concave

From Middle English concave, from Old French concave, from Latin concavus.

• (UK) IPA^(key): /ˈkɒn.keɪv/, /kɒnˈkeɪv/
• (US) IPA^(key): /ˈkɑn.keɪv/, /kɑnˈkeɪv/, /kənˈkeɪv/

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concave (comparative more concave, superlative most concave)

1. Curved like the inner surface of a sphere or bowl.
2. (geometry, not comparable, of a polygon) Not convex; having at least one internal angle greater than 180 degrees.
3. (functional analysis, not comparable, of a real-valued function on the reals) Satisfying the property that all segments connecting two points on the function's graph lie below the function.
4. Hollow; empty.
   • c. 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]:

     as concave […] as a worm-eaten nut

• convex

concave (plural concaves)

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.
7. (gambling) A playing card made concave for use in cheating.

   Coordinate term: convex

concave (third-person singular simple present concaves, present participle concaving, simple past and past participle concaved)

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

• concaver

Inherited from Old French concave, borrowed from Latin concavus.

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concave (plural concaves)

1. concave

• → Turkish: konkav

• “concave”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012.

concave

1. feminine plural of concavo

concave

1. vocative masculine singular of concavus