aphelion
noun
ˌap-ˈhēl-
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
Margherita Bassi, Smithsonian Magazine, 9 June 2025
Clouds that form during this time at the planet's equator are known as the aphelion cloud belt, according to NASA.
—Kenna Hughes-Castleberry, Space.com, 9 June 2025
The reverse is true at the most distant orbital point from the sun (aphelion), and the true sun moves ahead of the mean sun.
—Phil Plait, Scientific American, 5 June 2025
Not just Earth gets a perihelion and an aphelion each year.
—Jamie Carter, Forbes, 4 Jan. 2025
See All Example Sentences for aphelion
Cite this Entry
“Aphelion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/aphelion. Accessed 30 Jun. 2025.
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aphelion
noun
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