aphelion
UK /əˈfiː.lɪ.ən/ · US /əˈfi.li.ən/ noun
Forms aphelia aphelions
- noun (astronomy, also figuratively) The point in the elliptical orbit of a comet, planet, or other astronomical object, where it is farthest from the Sun.
Antonyms
Etymology
From New Latin aphēlium (whence English aphelium, now displaced) + -ion (used in the names of other apsides). Aphelium was formed from Ancient Greek ἀπο- (apo-, prefix meaning ‘away, from, off’) + ἥλῐος (hḗlĭos, “the sun”) (ultimately from Proto-Indo-European *sóh₂wl̥ (“the sun”)), modelled after New Latin apogaeum (“apogee”).
The plural form aphelia is from aphelion + -a (plural form of the suffix -on).
Webster’s 1913
Sources: Wiktionary · Webster’s 1913 — from the Wiktionary entry “aphelion”, CC BY-SA 4.0. Details