Epicycle

Webster's Practical Dictionary- A Practical Dictionary of the Englih Language · 1884 · p. 141

ep'T-si'kl, n. (Ptolemaic Astron.) A circle, whose center moves round in the circumference of a greater circle. — Epicy'cloid, -kloid, s-k, re. (Geom.) A curve generated i^/i by ence a of point a movable in the circle, cir cum fer which f ^// rolls on the inside or outside of the circumference of a fixed circle, as by the point a or a' in the circle A or A'.