audio vs recording

audio and recording both are nouns.

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

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

audio: a recording of acoustic signals
recording: a storage device on which information (sounds or images) have been recorded

audio (noun)	recording (noun)
the sound elements of television	the act of making a record (especially an audio record)
a recording of acoustic signals	a signal that encodes something (e.g., picture or sound) that has been recorded
an audible acoustic wave frequency	a storage device on which information (sounds or images) have been recorded
the audible part of a transmitted signal