tympanum vs tympanic cavity

tympanum and tympanic cavity both are nouns.

Word	Noun	Adjective	Verb	Adverb
tympanum	Yes	No	No	No
tympanic cavity	Yes	No	No	No

As nouns, tympanum and tympanic cavity are synonyms defined as:

tympanum and tympanic cavity: the main cavity of the ear; between the eardrum and the inner ear

Other synonyms of tympanum include middle ear.

tympanum (noun)	tympanic cavity (noun)
a large hemispherical brass or copper percussion instrument with a drumhead that can be tuned by adjusting the tension on it	the main cavity of the ear; between the eardrum and the inner ear
the membrane in the ear that vibrates to sound
the main cavity of the ear; between the eardrum and the inner ear