# trochoid

[troh-koid]

- Geometry. a curve traced by a point on a radius or an extension of the radius of a circle that rolls, without slipping, on a curve, another circle, or a straight line. Equation: x = aθ − b sin θ, y = a − b cos θ.

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- rotating on an axis, as a wheel.

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## Origin of trochoid^{}

Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

## Examples from the Web for trochoid

### Historical Examples

#### Then any point in the circumference of the half-crown will move through a curve called a ‘trochoid.’

BoatingW. B. Woodgate

## trochoid

- the curve described by a fixed point on the radius or extended radius of a circle as the circle rolls along a straight line

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- rotating or capable of rotating about a central axis
- anatomy (of a structure or part) resembling or functioning as a pivot or pulley

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## Word Origin

C18: from Greek trokhoeidēs circular, from trokhos wheel

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

## trochoid

(trō′koid′, trŏk′oid′)- Capable of or exhibiting rotation about a central axis.
- Permitting rotation, as a pivot.

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The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.