# trochoid

[troh-koid] /ˈtroʊ kɔɪd/
noun
1.
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 = b sin θ, y = ab cos θ.
2.
rotating on an axis, as a wheel.
Origin of trochoid
1695-1705
1695-1705; < Greek trochoeidḗs round like a wheel. See troche, -oid
Related forms
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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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.’

W. B. Woodgate
British Dictionary definitions for trochoid

## trochoid

/ˈtrəʊkɔɪd/
noun
1.
the curve described by a fixed point on the radius or extended radius of a circle as the circle rolls along a straight line
2.
rotating or capable of rotating about a central axis
3.
(anatomy) (of a structure or part) resembling or functioning as a pivot or pulley
Derived Forms
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
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trochoid in Medicine

trochoid tro·choid (trō'koid', trŏk'oid') or tro·choi·dal (trō-koid'l, trŏk-oid'l)

1. Capable of or exhibiting rotation about a central axis.

2. Permitting rotation, as a pivot.

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

Few English speakers likely know this word

### Word Value for trochoid

14
14
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