os sesamoideum vs os

os sesamoideum and os both are nouns.

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

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

os sesamoideum: any of several small round bones formed in a tendon where it passes over a joint
os: rigid connective tissue that makes up the skeleton of vertebrates

Other hypernyms of os sesamoideum include bone.

os sesamoideum (noun)	os (noun)
any of several small round bones formed in a tendon where it passes over a joint	rigid connective tissue that makes up the skeleton of vertebrates
	a mouth or mouthlike opening