n.
Pronunciation: ˌ e-p ə - ' s ī - ˌ klo ̇ id
Function: noun
Date: circa 1755
: a curve traced by a point on a circle that rolls on the outside of a fixed circle
– epi · cy · cloi · dal \ -s ī - ' klo ̇ i-d ə l \ adjective
epicycloid E, traced by point P, on circle R, rolling on fixed circle F