recording vs audio

recording and audio both are nouns.

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

As nouns, audio is a hyponym of recording; that is, audio is a word with a more specific, narrower meaning than recording:

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

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