auditory system vs hearing

auditory system and hearing both are nouns.

Word	Noun	Adjective	Verb	Adverb
auditory system	Yes	No	No	No
hearing	Yes	Yes	No	No

auditory system (noun)	hearing (noun)
the sensory system for hearing	the act of hearing attentively
	(law) a proceeding (usually by a court) where evidence is taken for the purpose of determining an issue of fact and reaching a decision based on that evidence
	the ability to hear; the auditory faculty
	a session (of a committee or grand jury) in which witnesses are called and testimony is taken
	the range within which a voice can be heard
	an opportunity to state your case and be heard

auditory system (adjective)	hearing (adjective)
	able to perceive sound