(in the Ptolemaic system) a small circle, around which a planet was thought to revolve, whose centre describes a larger circle (the deferent) centred on the earth
2.
a circle that rolls around the inside or outside of another circle, so generating an epicycloid or hypocycloid
Derived forms
epicyclic (ˌɛpɪˈsaɪklɪk, -ˈsɪklɪk) or epicyclical (ˌepiˈcyclical)
adjective
Word origin
C14: from Late Latin epicyclus, from Greek epikuklos; see epi-, cycle
epicycle in American English
(ˈɛpəˌsaɪkəl)
noun
1.
a circle whose center moves along the circumference of another, larger circle
term used to describe planetary motions in the Ptolemaic system
2. Geometry
a circle which generates a hypocycloid or epicycloid by rolling around the circumference of a fixed circle
Derived forms
epicyclic (ˌepiˈcyclic) (ˌɛpəˈsaɪklɪk)
adjective or ˌepiˈcyclical
Word origin
ME epicicle < LL epicyclus < Gr epikyklos < epi-, upon + kyklos, a circle: see cycle