ossicle vs os

ossicle and os both are nouns.

Word	Noun	Adjective	Verb	Adverb
ossicle	Yes	No	No	No
os	Yes	No	No	No

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

Other hypernyms of ossicle include bone.

ossicle (noun)	os (noun)
a small bone; especially one in the middle ear	rigid connective tissue that makes up the skeleton of vertebrates
	a mouth or mouthlike opening