from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The point nearest the sun in the orbit of a planet or other celestial body.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The point in the elliptical orbit of a planet or comet etc. where it is nearest to the Sun.
from the GNU version of the Collaborative International Dictionary of English
- n. That point of the orbit of a planet or comet which is nearest to the sun; -- opposed to
from The Century Dictionary and Cyclopedia
- n. That point of the orbit of a planet or comet in which it is at its least distance from the sun: opposed to aphelion.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. periapsis in solar orbit; the point in the orbit of a planet or comet where it is nearest to the sun
Alteration of New Latin perihēlium : peri- + Greek hēlios, sun.(American Heritage® Dictionary of the English Language, Fourth Edition)