Meaning of epitrochoid

ep•i•tro•choid

Pronunciation: (ep"i-trō'koid), [key]
— Geom. Geom.
  1. a plane curve generated by the motion of a fixed point on the radius or extension of the radius of a circle that rolls externally, without slipping, on a fixed circle. The epitrochoid is a generalization of the epicycloid.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.