from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The point on the orbit of a celestial body that is farthest from the sun.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The point in the elliptical orbit of a planet, comet, etc., where it is farthest from the sun.
from the GNU version of the Collaborative International Dictionary of English
- n. That point of a planet's or comet's orbit which is most distant from the sun, the opposite point being the perihelion.
from The Century Dictionary and Cyclopedia
- n. That point of a planet's or of a comet's orbit which is most distant from the sun: opposed to perihelion.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. apoapsis in solar orbit; the point in the orbit of a planet or comet that is at the greatest distance from the sun
From New Latin aphēlium : Greek apo-, apo- + Greek hēlios, sun.(American Heritage® Dictionary of the English Language, Fourth Edition)
Greek form of Latin aphelium, from Ancient Greek ἀπό (apo, "from") + ἥλιος (hēlios, "sun") (modelled after apogaeum). Compare perihelion. (Wiktionary)