audio frequency vs audio

audio frequency and audio both are nouns.

Word	Noun	Adjective	Verb	Adverb
audio frequency	Yes	No	No	No
audio	Yes	No	No	No

As nouns, audio frequency and audio are synonyms defined as:

audio frequency (noun)	audio (noun)
an audible acoustic wave frequency	the sound elements of television
	a recording of acoustic signals
	an audible acoustic wave frequency
	the audible part of a transmitted signal