USA vs Pennsylvania

USA and Pennsylvania both are nouns.

Word	Noun	Adjective	Verb	Adverb
USA	Yes	No	No	No
Pennsylvania	Yes	No	No	No

USA (noun)	Pennsylvania (noun)
the army of the United States of America; the agency that organizes and trains soldiers for land warfare	a university in Philadelphia, Pennsylvania
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 Mid-Atlantic state; one of the original 13 colonies, with capital Harrisburg
	one of the British colonies that formed the United States, with capital Philadelphia