from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of the four planets, Jupiter, Saturn, Uranus, and Neptune, with orbits outside that of Mars.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any planet of the Solar System whose orbit is located beyond the asteroid belt, i.e., any of Jupiter, Saturn, Uranus, or Neptune.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. (astronomy) a major planet whose orbit is outside the asteroid belt (Jupiter, Saturn, Uranus, Neptune, Pluto)
Sorry, no etymologies found.