Mississippi River vs USA

Mississippi River and USA both are nouns.

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

Mississippi River (noun)	USA (noun)
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	the army of the United States of America; the agency that organizes and trains soldiers for land warfare
	North American republic containing 50 states - 48 conterminous states in North America plus Alaska in northwest North America and the Hawaiian Islands in the Pacific Ocean; achieved independence in 1776