solar system vs Pluto

solar system and Pluto both are nouns.

Word	Noun	Adjective	Verb	Adverb
solar system	Yes	No	No	No
Pluto	Yes	No	No	No

solar system (noun)	Pluto (noun)
the sun with the celestial bodies that revolve around it in its gravitational field	a large asteroid that was once thought to be the farthest known planet from the sun; it has an elliptical orbit
	(Roman mythology) god of the underworld; counterpart of Greek Hades
	a cartoon character created by Walt Disney, a red-colored, medium-sized, short-haired dog with black ears