vestibular system vs vestibular apparatus

vestibular system and vestibular apparatus both are nouns.

Word	Noun	Adjective	Verb	Adverb
vestibular system	Yes	No	No	No
vestibular apparatus	Yes	No	No	No

As nouns, vestibular system and vestibular apparatus are synonyms defined as:

vestibular system and vestibular apparatus: organs mediating the labyrinthine sense; concerned with equilibrium

vestibular system (noun)	vestibular apparatus (noun)
organs mediating the labyrinthine sense; concerned with equilibrium	organs mediating the labyrinthine sense; concerned with equilibrium