concave

English

Top: a spoon with its convex side up.
Bottom: a spoon with its concave side up.

A concave polygon.

A concave (concave downwards) function.

Etymology

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

Pronunciation

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

  • Audio (US)

    (file)

Adjective

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

Antonyms

• convex

Derived terms

• concave envelope
• concave function
• concavely
• concaveness
• concavity
• double concave

 

Translations

curved inward

• Arabic: مُقَعَّر (muqaʕʕar), مُجَوَّف (mujawwaf)
• Armenian: գոգավոր (hy) (gogavor)
• Asturian: cóncavu
• Bengali: অবতল (bn) (obotol)
• Bulgarian: вдлъбнат (vdlǎbnat)
• Catalan: còncau (ca)
• Chinese:

  Mandarin: 凹 (zh) (āo)

• Cornish: kowgrom
• Czech: vydutý, konkávní (cs)
• Danish: konkav
• Dutch: hol (nl)
• Esperanto: kava
• Estonian: nõgus
• Faroese: innskaraður, innhjólaður
• Finnish: kovera (fi), konkaavi (fi)
• French: concave (fr)
• Galician: cóncavo (gl)
• German: konkav (de), nach innen gewölbt, eingewölbt
• Greek: κοίλος (el) (koílos)
• Hawaiian: ʻeʻele
• Hungarian: homorú (hu), konkáv (hu)
• Icelandic: íhvolfur
• Italian: concavo (it)
• Japanese: 凹面 (おうめん, ōmen)
• Kazakh: ойыс (oiys)
• Korean: 요면 (yomyeon)
• Latin: concavus
• Maori: areare
• Norwegian:

  Bokmål: konkav

  Nynorsk: konkav

• Persian: کاو (fa) (kâv)
• Polish: wklęsły (pl)
• Portuguese: côncavo (pt)
• Romanian: concav (ro)
• Russian: во́гнутый (ru) (vógnutyj)
• Slovak: dutý, vydutý, konkávny
• Spanish: cóncavo (es)
• Swedish: konkav (sv)
• Tagalog: malukong
• Thai: เว้า (th) (wáo)
• Turkish: konkav (tr), içbükey (tr)
• Welsh: ceugrwm (cy) m, ceugrom f

Noun

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

Translations

A concave surface or curve

• Bulgarian: вдлъбнатина (bg) (vdlǎbnatina)
• Kurdish:

  Northern Kurdish: rûçal (ku)

• Russian: невы́пуклый (ru) (nevýpuklyj)
• Thai: รูปร่างที่นูน

Verb

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.

Derived terms

• concaver

Translations

To render concave, or increase the degree of concavity.

• Bulgarian: вдлъбвам (vdlǎbvam)

French

Etymology

Inherited from Old French concave, borrowed from Latin concavus.

Pronunciation

• Audio

  (file)

Adjective

concave (plural concaves)

1. concave

Descendants

• → Turkish: konkav

Further reading

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

Italian

Adjective

concave

1. feminine plural of concavo

Latin

Adjective

concave

1. vocative masculine singular of concavus