DC vs USA

DC and USA both are nouns.

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

DC (noun)	USA (noun)
the district occupied entirely by the city of Washington; chosen by George Washington as the site of the capital of the United States and created out of land ceded by Maryland and Virginia	the army of the United States of America; the agency that organizes and trains soldiers for land warfare
an electric current that flows in one direction steadily	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