different between convex vs afocal

English

Etymology

Borrowed from Middle French convexe, from Latin convexus (“arched”).

Pronunciation

• (Received Pronunciation) IPA^(key): /?k?nv?ks/
• (General American) IPA^(key): /?k?nv?ks/
• The noun was often stressed on the second syllable by early writers, such as Milton, and occasionally by later poets.

Adjective

convex (comparative more convex, superlative most convex)

1. curved or bowed outward like the outside of a bowl or sphere or circle
   • 1837, William Whewell, History of the Inductive Sciences

     Drops of water naturally form themselves into figures with a convex surface.

2. (mathematics, not comparable, of a set in Euclidean space) arranged such that for any two points in the set, a straight line between the two points is contained within the set.
3. (geometry, not comparable, of a polygon) having no internal angles greater than 180 degrees.
4. (functional analysis, not comparable, of a real-valued function on the reals) having an epigraph which is a convex set.

Antonyms

• concave

Derived terms

Translations

Noun

convex (plural convexes)

1. Any convex body or surface.
   • 1714, Thomas Tickell, Royal Progress

     Half heaven's convex glitters with the flame.

2. (gambling) A playing card made convex for use in cheating.

   Coordinate term: concave

3. (gambling) A small convex mirror used to cheat by observing other players' cards.

   Synonym: shiner

   • 2019, John Philip Quinn, Fools of Fortune; or, Gambling and Gamblers

     Of all the devices for defrauding at poker, the “shiner,” or “convex” […] Modern convexes are also considerably larger than those of former days.

References

• John A. Simpson and Edward S. C. Weiner, editors (1989) , “convex”, in The Oxford English Dictionary, 2nd edition, Oxford: Clarendon Press, ?ISBN

Catalan

Etymology

Borrowed from Latin convexus.

Pronunciation

• (Balearic, Valencian) IPA^(key): /kom?v?ks/
• (Central) IPA^(key): /kum?b?ks/

Adjective

convex (feminine convexa, masculine plural convexos, feminine plural convexes)

1. convex

Antonyms

• còncau

Related terms

• convexitat

Further reading

• “convex” in Diccionari de la llengua catalana, segona edició, Institut d’Estudis Catalans.

Dutch

Etymology

Borrowed from French convexe, from Latin convexus.

Pronunciation

• IPA^(key): /k?n?v?ks/
• Hyphenation: con?vex
• Rhymes: -?ks

Adjective

convex (comparative convexer, superlative meest convex or convext)

1. convex

   Synonym: bolrond

   Antonym: concaaf

Inflection

Derived terms

• biconvex
• convexiteit

Romanian

Etymology

From French convexe, from Latin convexus.

Adjective

convex m or n (feminine singular convex?, masculine plural convec?i, feminine and neuter plural convexe)

1. convex

Declension

English

Etymology

a- +? focal

Adjective

afocal (not comparable)

1. (optics, of an imaging system) Not focused
2. (optics, of a lens) Neither concave or convex (focal point at infinity)

Derived terms

• afocality
• afocally

Translations

French

Etymology

a- +? focal

Adjective

afocal (feminine singular afocale, masculine plural afocaux, feminine plural afocales)

1. afocal

Portuguese

Adjective

afocal m or f (plural afocais, comparable)

1. (optics, of a lens) afocal (having a focal point at infinity)

Romanian

Etymology

From French afocal

Adjective

afocal m or n (feminine singular afocal?, masculine plural afocali, feminine and neuter plural afocale)

1. afocal

Declension