audiotape vs audio

audiotape and audio both are nouns.

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

As nouns, audio is a hypernym of audiotape; that is, audio is a word with a broader meaning than audiotape:

Other hypernyms of audiotape include audio recording, sound recording, tape, tape recording, taping.

audiotape (noun)	audio (noun)
magnetic tape for use in recording sound	the sound elements of television
a tape recording of sound	a recording of acoustic signals
	an audible acoustic wave frequency
	the audible part of a transmitted signal