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1. In Ptolemaic cosmology, a small circle, the center of which moves on the circumference of a larger circle at whose center is the earth and the circumference of which describes the orbit of one of the planets around the earth.
2. Mathematics A circle whose circumference rolls along the circumference of a fixed circle, thereby generating an epicycloid or a hypocycloid.
[Middle English epicicle, from Late Latin epicyclus, from Greek epikuklos : epi-, epi- + kuklos, circle; see kwel- in Indo-European roots.]
ep′i·cyc′lic (-sĭk′lĭk, -sī′klĭk) adj.
1. (Astronomy) astronomy (in the Ptolemaic system) a small circle, around which a planet was thought to revolve, whose centre describes a larger circle (the deferent) centred on the earth
2. (Mathematics) a circle that rolls around the inside or outside of another circle, so generating an epicycloid or hypocycloid
[C14: from Late Latin epicyclus, from Greek epikuklos; see epi-, cycle]
epicyclic, ˌepiˈcyclical adj
ep•i•cy•cle(ˈɛp əˌsaɪ kəl)
1. a circle whose center moves around in the circumference of a larger circle: used in Ptolemaic astronomy to account for irregularities in planetary motion.
2. a circle that rolls, externally or internally, without slipping, on another circle, generating an epicycloid or hypocycloid.
[1350–1400; Middle English < Middle French < Late Latin epicyclus < Greek epíkyklos. See epi-, cycle]
ep`i•cy′clic (-ˈsaɪ klɪk, -ˈsɪk lɪk) adj.
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|Noun||1.||epicycle - a circle that rolls around (inside or outside) another circle; generates an epicycloid or hypocycloid|
circle - ellipse in which the two axes are of equal length; a plane curve generated by one point moving at a constant distance from a fixed point; "he calculated the circumference of the circle"
n → Epizykel m