# epicycloid

[ ep-uh-sahy-kloid ]

/ ˌɛp əˈsaɪ klɔɪd /

### 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].

## QUIZZES

#### CAN YOU FEEL THE WEAL WITH THIS WORD OF THE DAY QUIZ?

Did you collect all of last week’s words, but eftsoons forget what they mean? Don’t worry, we’re here to jog your memory. See how many words from the week of May 18 to 24 you can get right!

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weal

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. 2020

## Example sentences from the Web for epicycloid

## 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.