siege of Vicksburg vs Mississippi

siege of Vicksburg and Mississippi both are nouns.

Word	Noun	Adjective	Verb	Adverb
siege of Vicksburg	Yes	No	No	No
Mississippi	Yes	No	No	No

siege of Vicksburg (noun)	Mississippi (noun)
a decisive battle in the American Civil War (1863); after being besieged for nearly seven weeks the Confederates surrendered	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