# epicycloid

[ ep-uh-sahy-kloid ]

/ ˌɛp əˈsaɪ klɔɪd /

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### noun Geometry.

a curve generated by the motion of a point on the circumference of a circle that rolls externally, without slipping, on a fixed circle. Equation: x = (a + b) cos(θ) − b cos[(a + b)θ/b] and y = (a + b) sin(θ) − b sin[(a + b)θ/b].

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On the farm, the feed for chicks is significantly different from the roosters’; ______ not even comparable.

Compare epitrochoid.

## OTHER WORDS FROM epicycloid

ep·i·cy·cloi·dal, adjective## Words nearby epicycloid

Epicureanism, Epicurus, epicuticle, epicycle, epicyclic train, epicycloid, epicycloidal gear, epicycloidal wheel, epicystitis, epicystotomy, Epidaurus

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Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

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## British Dictionary definitions for epicycloid

epicycloid

/ (ˌɛpɪˈsaɪklɔɪd) /

### noun

the curve described by a point on the circumference of a circle as this circle rolls around the outside of another fixed circle, the two circles being coplanarCompare hypocycloid, cycloid (def. 4)

## Derived forms of epicycloid

epicycloidal, adjectiveCollins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

## Scientific definitions for epicycloid

epicycloid

[ ĕp′ĭ-sī′kloid′ ]

The curve described by a point on the circumference of a circle as the circle rolls on the outside of the circumference of a second, fixed circle.

The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.