Epicycle

2 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Epicycle \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.
        [1913 Webster]
  
              The schoolmen were like astronomers which did feign
              eccentrics, and epicycles, and such engines of orbs.
                                                    --Bacon.
        [1913 Webster]
  
     2. (Mech.) A circle which rolls on the circumference of
        another circle, either externally or internally.
        [1913 Webster] epicyclic

From WordNet (r) 2.0 [wn]:

  epicycle
       n : a circle that rolls around (inside or outside) another
           circle; generates an epicycloid or hypocycloid