river vs Mississippi

river and Mississippi both are nouns.

Word	Noun	Adjective	Verb	Adverb
river	Yes	No	No	No
Mississippi	Yes	No	No	No

river (noun)	Mississippi (noun)
a large natural stream of water (larger than a creek)	a state in the Deep South on the gulf of Mexico; one of the Confederate States during the American Civil War
	a major North American river and the chief river of the United States; rises in northern Minnesota and flows southward into the Gulf of Mexico