Meaning

noun apoapsis in solar orbit; the point in the orbit of a planet or comet that is at the greatest distance from the sun

originFrom 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…

Etymology from Wiktionary, CC BY-SA 3.0