Wormian bone vs os

Wormian bone and os both are nouns.

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

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

Wormian bone: any of the tiny soft bones found in the sutures between cranial bones
os: rigid connective tissue that makes up the skeleton of vertebrates

Other hypernyms of Wormian bone include bone.

Wormian bone (noun)	os (noun)
any of the tiny soft bones found in the sutures between cranial bones	rigid connective tissue that makes up the skeleton of vertebrates
	a mouth or mouthlike opening