Definition

A small circle that moves along the edge of a larger circle, often used in ancient astronomy to explain the orbits of planets around the Earth.

Example

In ancient astronomy, the concept of an epicycle was used to describe the complex movements of planets.

Conversation

Have you ever heard of the term epicycle?

Yeah, I think it has something to do with astronomy, right?

Exactly! It's a concept from Ptolemaic cosmology.

That's interesting! I love how complex those models can be.

Synonyms & Antonyms

Root Explanation

Epicycle → It is formed from "epi-" (meaning upon or above) and "kuklos" (meaning circle). The term refers to a small circle whose center moves around the circumference of a larger one, thus describing a circular motion upon another circle.

Memory Tip

Imagine a smaller circle moving 'upon' ('epi-') a larger circle ('kuklos') — this helps you remember that an epicycle is a circle on top of another circle.

Visually Confused Words