corpus sternum vs os

corpus sternum and os both are nouns.

Word	Noun	Adjective	Verb	Adverb
corpus sternum	Yes	No	No	No
os	Yes	No	No	No

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

Other hypernyms of corpus sternum include bone.

corpus sternum (noun)	os (noun)
the large central part of the breastbone	rigid connective tissue that makes up the skeleton of vertebrates
	a mouth or mouthlike opening