\Ep"i*cy`cle\, n. [L. epicyclus, Gr. ?; 'epi` upon + ?
circle. See {Cycle}.]
1. (Ptolemaic Astron.) A circle, whose center moves round in
   the circumference of a greater circle; or a small circle,
   whose center, being fixed in the deferent of a planet, is
   carried along with the deferent, and yet, by its own
   peculiar motion, carries the body of the planet fastened
   to it round its proper center.
         The schoolmen were like astronomers which did feign
         eccentries, and epicycles, and such engines of orbs.
                                               --Bacon.
2. (Mech.) A circle which rolls on the circumference of
   another circle, either externally or internally.