U.S.A. vs Bluegrass State

U.S.A. and Bluegrass State both are nouns.

Word	Noun	Adjective	Verb	Adverb
U.S.A.	Yes	No	No	No
Bluegrass State	Yes	No	No	No

U.S.A. (noun)	Bluegrass State (noun)
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	a state in east central United States; a border state during the American Civil War; famous for breeding race horses