shoulder bone vs os

shoulder bone and os both are nouns.

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

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

shoulder bone: either of two flat triangular bones one on each side of the shoulder in human beings
os: rigid connective tissue that makes up the skeleton of vertebrates

Other hypernyms of shoulder bone include bone.

shoulder bone (noun)	os (noun)
either of two flat triangular bones one on each side of the shoulder in human beings	rigid connective tissue that makes up the skeleton of vertebrates
	a mouth or mouthlike opening