1. of, relating to, or produced by an epicycle; involving the motion of a point on a circle that itself revolves around another circle
Usage: technical; mathematics and astronomy
2. of or relating to an epicyclic gear system, in which one or more gears revolve around a central gear
Usage: technical; engineering and mechanics

Examples

• The ancient astronomers used epicyclic models to explain the apparent motion of planets in the sky.
• An epicyclic gear train allows for multiple gear ratios in a compact space.
• The epicyclic motion of the moon around Earth, combined with Earth's orbit around the Sun, creates complex patterns.
• Modern automatic transmissions often use epicyclic gear systems for smooth power delivery.
• Ptolemy's epicyclic theory attempted to account for retrograde motion observed in planetary movements.