membranous labyrinth vs inner ear

membranous labyrinth and inner ear both are nouns.

Word	Noun	Adjective	Verb	Adverb
membranous labyrinth	Yes	No	No	No
inner ear	Yes	No	No	No

membranous labyrinth (noun)	inner ear (noun)
the sensory structures of the inner ear including the labyrinthine receptors and the cochlea; contained within the bony labyrinth	a complex system of interconnecting cavities; concerned with hearing and equilibrium