Tombigbee vs river

Tombigbee and river both are nouns.

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

Tombigbee (noun)	river (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 large natural stream of water (larger than a creek)