USA vs Keystone State

USA and Keystone State both are nouns.

Word	Noun	Adjective	Verb	Adverb
USA	Yes	No	No	No
Keystone State	Yes	No	No	No

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