aphelion

noun

aph·​elion a-ˈfēl-yən  ˌap-ˈhēl- 

plural aphelia a-ˈfēl-yə 

ˌap-ˈhēl-

: 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.

Examples of aphelion in a Sentence

Recent Examples on the Web

At the same time, Earth will be close to aphelion, when the sun appears marginally smaller than average in the sky. — Jamie Carter, Forbes.com, 21 Mar. 2026

However, the dates of aphelion and perihelion (when Earth is its closest to the sun for the year) drift over the centuries. — Jamie Carter, Space.com, 22 Feb. 2026

The band of clouds that forms across the planet’s equator at this time of year, called the aphelion cloud belt, is on prominent display in Odyssey’s new panorama. — Eric Lagatta, USA Today, 18 June 2025

Word History

Etymology

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

First Known Use

1656, in the meaning defined above

Rhymes for aphelion

• cornelian

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Kids Definition

aphelion

noun

aph·​elion a-ˈfēl-yən 

plural aphelia -yə 

: the point in the orbit of a heavenly body (as a planet) that is farthest from the sun