epicycle

See also: épicycle

English

Etymology

From Latin epicyclus, from Ancient Greek ἐπίκυκλος (epíkuklos), from ἐπί (epí, “upon”) + κύκλος (kúklos, “circle”).

Pronunciation

• (UK) IPA^(key): /ˈɛpɪˌsaɪkəl/

• Audio (US):

  (file)

Noun

epicycle (plural epicycles)

1. (astronomy) A small circle whose centre is on the circumference of a larger circle; in Ptolemaic astronomy it was seen as the basis of revolution of the "seven planets", given a fixed central Earth.
   • 1603, Michel de Montaigne, translated by John Florio, The Essayes […], London: […] Val[entine] Simmes for Edward Blount […], →OCLC:
     , Folio Society, 2006, vol.1, p.155:

     Is it not [Philosophie], that […] teacheth miserie, famine and sicknesse to laugh? Not by reason of some imaginarie Epicicles, but by naturall and palpable reasons.

2. (geometry) Any circle whose circumference rolls around that of another circle, thus creating a hypocycloid or epicycloid.
3. (organic chemistry) A ring of atoms joining parts of an already cyclic compound
4. (figuratively) An ad hoc complication added to a model to make it fit the known data
   • 1978, The Journal of the Siam Society, volumes 66-67, page 152:

     If two chronicles seemed contradictory, instead of trying to choose between them, a rationalization (epicycle) was devised to cover both.

   • 1998, Paul Joseph Kelly, Impartiality, Neutrality and Justice: Re-reading Brian Barry’s Justice as Impartiality, page 12:

     Rather than solve the theoretical problem of how to produce a method of political ethics, the contractarian device introduces an unnecessary theoretical epicycle into what is otherwise a coherent account of social justice in particular and political morality in general.

Derived terms

• epicyclic

Translations

a small circle whose centre is on the circumference of a larger circle

• Bulgarian: епицикъл (epicikǎl)
• Catalan: epicicle
• Czech: epicykl m
• Danish: epicykel
• Dutch: epicykels
• Finnish: episykli
• French: épicycle (fr)
• German: Epizykel
• Hebrew: אפיציקל
• Icelandic: aukahringur m, hjáhringur m
• Ido: epiciklo (io)
• Italian: epiciclo (it)
• Kabuverdianu: episiklu, epiciclo
• Malayalam: അധിചക്രം (adhicakraṁ)
• Manx: far-chiarkyl m
• Middle Persian: [script needed] (ywg /⁠ǰuγ⁠/)
• Norwegian: episyklus
• Persian: تدویر (fa) (tadvir), فلک تدویر (fa) (falak-e tadvir)
• Portuguese: epiciclo m
• Russian: эпицикл (ru) (epicikl)
• Slovak: epicyklus
• Spanish: epiciclo m
• Swedish: epicykel

any circle whose circumference rolls around that of another circle

• Finnish: episykli
• Manx: far-chiarkyl m

The translations below need to be checked and inserted above into the appropriate translation tables. See instructions at Wiktionary:Entry layout § Translations.

Translations to be checked

• Swedish: ^{(please verify)} epicykel c