Tombigbee River vs Mississippi

Tombigbee River and Mississippi both are nouns.

Word	Noun	Adjective	Verb	Adverb
Tombigbee River	Yes	No	No	No
Mississippi	Yes	No	No	No

Tombigbee River (noun)	Mississippi (noun)
a river that rises in northeastern Mississippi and flows southward through western Alabama to join the Alabama River and form the Mobile River	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