from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of the four planets, Mercury, Venus, Earth, or Mars, that are nearest the sun and have similar size and density.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any planet of the solar system or any exoplanet which is "Earth-like" in the sense that it is composed primarily of metals and rock, in contrast to a planet which is a gas giant.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a planet having a compact rocky surface like the Earth's; the four innermost planets in the solar system
Sorry, no etymologies found.