epicycle

listen to the pronunciation of epicycle
English - English
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

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

Any circle whose circumference rolls around that of another circle, thus creating a hypocycloid or epicycloid
a circle that rolls upon the external or internal circumference of another circle
A circle which rolls on the circumference of another circle, either externally or internally
a small circle, moving around the circumference of a larger circle having the earth at its centre; the supposed orbit of a planet
A construct of the geocentric model of the solar system which was necessary to explain observed planetary motions Each planet rides on a small epicycle whose center in turn rides on a larger circle (the deferent)
The small circle followed by a planet in the Ptolemaic theory The center of the epicycle follows a larger circle around earth
a device in Ptolemy's Earth-centered model that makes a planet execute a small circular motion around a point that is itself in a circular orbit around the Earth It was used to explain retrograde motion
Smaller circle in the Ptolemaic system along which the planet moves while the center of the circle revolves about its deferent
A circular orbit of a body in the Ptolemaic system, the center of which revolves about another circle (the deferent)
A circle, whose center moves round in the circumference of a greater circle; or a small circle, whose center, being fixed in the deferent of a planet, is carried along with the deferent, and yet, by its own peculiar motion, carries the body of the planet fastened to it round its proper center
The small circle rotating on the deferent on which a planet moves in the geocentric system of astronomy
in the Ptolemaic system, a small circular orbit of a body, the center of which follows a larger circle (the deferent) around Earth
{i} circle whose centre is on circumference of a greater circle
a circle that rolls around (inside or outside) another circle; generates an epicycloid or hypocycloid
An epicycle is a small circle that some astronomers used to think a planet followed while it traveled in a much larger orbit Basically, it's a make believe loopty-loop in a planet's orbit While the epicycle does not really happen, it was used by Ptolemy to explain the "backward motion ", or retrograde motion, of all the planets that are further from the sun than we are Ptolemy used epicycles to support his belief that the earth was the center of the universe, which is also not true
A circle around a point which (in the simplest form of Ptolemy's system) moved steadily around the celestial sphere Greek astronomers proposed that planets moved along epicycles around the Sun or around other points which circled around the sky; later additional corrections were added The theory of epicycles was the earliest explanation for the irregular apparent motion of the planets--prograde (forward), then retrograde
epicyclic
of or relating to an epicycle; "epicyclic gear train
epicyclic
of, or relating to an epicycle
epicyclic
Pertaining to, resembling, or having the motion of, an epicycle
epicyclic
planetary
epicycle

    Hyphenation

    ep·i·cy·cle

    Pronunciation

    Etymology

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