aphelion

play
noun aph·elion \a-ˈfēl-yən, ˌap-ˈhēl-\

Definition of aphelion

plural

aphelia

play \a-ˈfēl-yə, ˌap-ˈhēl-\
  1. :  the point farthest from the sun in the path of an orbiting celestial body (such as a planet) — compare perihelion

Did You Know?

Aphelion and perihelion are troublesome terms. Which one means a planet is nearest to the sun and which means it is farthest away? An etymology lesson may help you keep those words straight. Just remember that the "ap" of aphelion derives from a Latin prefix that means "away from" (the mnemonic "'A' for 'away'" can help too); peri-, on the other hand, means "near." And how are aphelion and perihelion related to the similar-looking astronomical pair, apogee and perigee? Etymology explains again. The "helion" of aphelion and perihelion is based on the Greek word hēlios, meaning "sun," while the "gee" of apogee and perigee is based on gaia, meaning "earth." The first pair describes distance in relation to the sun, the second in relation to the earth.

Origin and Etymology of aphelion

New Latin, from apo- + Greek hēlios sun — more at solar


First Known Use: 1656


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