dentin vs os

dentin and os both are nouns.

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

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

Other hypernyms of dentin include bone.

dentin (noun)	os (noun)
bone (calcified tissue) surrounding the pulp cavity of a tooth	rigid connective tissue that makes up the skeleton of vertebrates
a calcareous material harder and denser than bone that comprises the bulk of a tooth	a mouth or mouthlike opening