epicycle

(ep′ə sī′kəl)

noun

a circle whose center moves along the circumference of another, larger circle: term used to describe planetary motions in the Ptolemaic system
Geom. a circle which generates a hypocycloid or epicycloid by rolling around the circumference of a fixed circle

Origin: ME epicicle < LL epicyclus < Gr epikyklos < epi-, upon + kyklos, a circle: see cycle

Related Forms:

See epicycle in American Heritage Dictionary 4

noun

In Ptolemaic cosmology, a small circle, the center of which moves on the circumference of a larger circle at whose center is the earth and the circumference of which describes the orbit of one of the planets around the earth.
Mathematics A circle whose circumference rolls along the circumference of a fixed circle, thereby generating an epicycloid or a hypocycloid.

Origin:

Origin: Middle English epicicle

Origin: , from Late Latin epicyclus

Origin: , from Greek epikuklos

Origin: : epi-, epi-

Origin: + kuklos, circle; see k^wel-¹ in Indo-European roots

Related Forms: