tympanic bone vs os

tympanic bone and os both are nouns.

Word	Noun	Adjective	Verb	Adverb
tympanic bone	Yes	No	No	No
os	Yes	No	No	No

As nouns, os is a hypernym of tympanic bone; that is, os is a word with a broader meaning than tympanic bone:

Other hypernyms of tympanic bone include bone.

tympanic bone (noun)	os (noun)
the bone enclosing the middle ear	rigid connective tissue that makes up the skeleton of vertebrates
	a mouth or mouthlike opening