Dictionary
ep•i•cy•cloid
Pronunciation: (ep"u-sī'kloid), [key]—
n. Geom.
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]. Cf.
epitrochoid.Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.