- 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].
Origin of epicycloid
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for epicycloid
It follows that a line from B to M will always be tangential to the epicycloid.
Suppose b a tracing point on b, then as b rolls on a it will describe the epicycloid a b.
It is impossible to mill out even a convex cycloid or epicycloid, by the means and in the manner above described.
But if a circle be made to roll along the circumference of another circle, it becomes an epicycloid (which see).The Sailor's Word-Book
William Henry Smyth
The epicycloid shown is termed the “three-cusped epicycloid” or the “epicycloid of Cremona.”
- 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.