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Glite Dictionary
epicyclic

epicyclic

1 9.9
A system where a small circle moves around a larger circle, used in gears and planet models
  • adjective
  • /ˌɛpɪˈsaɪklɪk/
  • Specialized
translation icon : epicíclico
  • The engineers designed an epicyclic gearbox to improve the efficiency of the vehicle's transmission system.

Examples

  • In ancient astronomy, the planets were thought to follow epicyclic paths around the Earth.

  • Here she claims "good lines" should be "epicyclic":

    Academic text (1996)

  • So let me add that to our information, Depends who you believe invented this epicyclic lunar theory.

  • The dictionary definition of epicyclic, "a circle in which a planet moves, which has a center that is itself carried around at the same time on the circumference of a larger circle."

    Academic text (1996)

  • You've got yourself a custom-made epicyclic, concentric reduction gearbox.

    Planes: Fire & Rescue (2014)

  • A very exciting moment for me was at the planetarium when the machine was run fast for the purpose of explaining its operation: a planet moved along a straight line, then suddenly made a complete loop of 360 degrees off to one side, and then went off in a straight line in its original direction, epicyclic motion.

    Academic text (1998)

  • The clock mechanism uses an epicyclic arrangement of gears to provide accurate timekeeping.

Synonyms

epicyclical
vsepicyclic
  • Specialized
9.9

Having a small wheel that turns around a larger wheel

is the variant that uses a different adjective ending in writing
gyratory
vsepicyclic
7.9

Moving in a circular or spiral way

is specific to the smaller-on-larger circular motion used in astronomy and gear trains

Compounds

epicyclic gear
  • Specialized
8.8

A gear that turns around a central gear to change speed or turning force

epicyclic gear train
  • Specialized
6.5

A set of gears where one gear moves around a central gear while spinning to change speed or force

epicyclic train
  • Specialized
9.9

A set of gears where one gear turns around another fixed gear in a gearbox

Surface Forms

epicyclic positive

Morphology

epicyclic = epicycle (opaque) = epi + cycle + ic

Forming an adjective from the noun 'epicycle' with the regular suffix '-ic' is a standard and predictable morphological step.

Etymology

Epicyclic comes from the Greek parts epi- 'upon' and kyklos 'circle', and you can see the same cycle in words like bicycle. Old astronomers used an epicycle as a 'small circle on top of a larger circle' to explain planet paths, so epicyclic now describes systems or gears where one circle turns on or around another.