DC vs direct current

DC and direct current both are nouns.

Word	Noun	Adjective	Verb	Adverb
DC	Yes	No	No	No
direct current	Yes	No	No	No

As nouns, DC and direct current are synonyms defined as:

DC and direct current: an electric current that flows in one direction steadily

Other synonyms of DC include direct electric current.

DC (noun)	direct current (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	an electric current that flows in one direction steadily
an electric current that flows in one direction steadily