major planet

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun astronomy Any of the 8 celestial bodies which orbit the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
• noun astronomy Those planets that are larger than the Earth; specifically Jupiter , Saturn , Uranus , Neptune (in the Solar System)
• noun astronomy a celestial body that fits the 2006 IAU definition of planet

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun (astronomy) any of the nine large celestial bodies in the solar system that revolve around the sun and shine by reflected light; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto in order of their proximity to the sun; viewed from the constellation Hercules, all the planets rotate around the sun in a counterclockwise direction