Louisiana vs Red River of the South

Louisiana and Red River of the South both are nouns.

Word	Noun	Adjective	Verb	Adverb
Louisiana	Yes	No	No	No
Red River of the South	Yes	No	No	No

Louisiana (noun)	Red River of the South (noun)
a state in southern United States on the Gulf of Mexico; one of the Confederate states during the American Civil War	a tributary of the Mississippi River that flows eastward from Texas along the southern boundary of Oklahoma and through Louisiana