epicycloid: Meaning and Definition of

ep•i•cy•cloid

1. 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:= (a + b) cos &thgr; − b cos [(a + b)&thgr;/b] and y = (a + b) sin &thgr; − b sin [(a + b)&thgr;/b]. Cf. epitrochoid. x