alternating current vs AC

alternating current and AC both are nouns.

Word	Noun	Adjective	Verb	Adverb
alternating current	Yes	No	No	No
AC	Yes	No	No	No

As nouns, alternating current and AC are synonyms defined as:

alternating current and AC: an electric current that reverses direction sinusoidally

Other synonyms of alternating current include alternating electric current.

alternating current (noun)	AC (noun)
an electric current that reverses direction sinusoidally	an electric current that reverses direction sinusoidally