tarsal vs os

tarsal and os both are nouns.

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

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

Other hypernyms of tarsal include bone.

tarsal (noun)	os (noun)
any bone of the tarsus	rigid connective tissue that makes up the skeleton of vertebrates
	a mouth or mouthlike opening

tarsal (adjective)	os (adjective)
of or relating to or near the tarsus of the foot