Niagara vs U.S.A.

Niagara and U.S.A. both are nouns.

Word	Noun	Adjective	Verb	Adverb
Niagara	Yes	No	No	No
U.S.A.	Yes	No	No	No

Niagara (noun)	U.S.A. (noun)
a river flowing from Lake Erie into Lake Ontario; forms boundary between Ontario and New York	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
waterfall in Canada is the Horseshoe Falls; in the United States it is the American Falls