solar system vs major planet

solar system and major planet both are nouns.

Word	Noun	Adjective	Verb	Adverb
solar system	Yes	No	No	No
major planet	Yes	No	No	No

solar system (noun)	major planet (noun)
the sun with the celestial bodies that revolve around it in its gravitational field	(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