epicycle

noun

epi·​cy·​cle ˈe-pə-ˌsī-kəl 

1

in Ptolemaic astronomy : a circle in which a planet moves and which has a center that is itself carried around at the same time on the circumference of a larger circle

2

: a process going on within a larger one

epicyclic

ˌe-pə-ˈsī-klik 

-ˈsi-klik

adjective

Examples of epicycle in a Sentence

Recent Examples on the Web

Amid these complications, Tomas proves to be a spontaneous provocateur, producing further epicycles of enmity and turmoil. —Richard Brody, The New Yorker, 8 Aug. 2023

The Ptolemaic model depicted planets moving around Earth in a big circle, known as a deferent, then going around a smaller circle while retrograding, called an epicycle. —Carlie Procell, USA Today, 19 Apr. 2023

In order to reconcile circular orbits with actual planetary behavior, Copernicus continued the tradition, developed by Ptolemy, of arguing that planets spin on wheels, known as epicycles. —National Geographic, 9 Apr. 2019

Word History

Etymology

Middle English epicicle, from Late Latin epicyclus, from Greek epikyklos, from epi- + kyklos circle — more at wheel

First Known Use

14th century, in the meaning defined at sense 1

Kids Definition

epicycle

noun

epi·​cy·​cle ˈep-ə-ˌsī-kəl 

: a circle according to an early astronomy theory in which a planet moves and which has a center that is itself carried around at the same time on the circumference of a larger circle