cannon bone vs os

cannon bone and os both are nouns.

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

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

cannon bone: greatly developed metatarsal or metacarpal bone in the shank or cannon part of the leg in hoofed mammals
os: rigid connective tissue that makes up the skeleton of vertebrates

Other hypernyms of cannon bone include bone.

cannon bone (noun)	os (noun)
greatly developed metatarsal or metacarpal bone in the shank or cannon part of the leg in hoofed mammals	rigid connective tissue that makes up the skeleton of vertebrates
	a mouth or mouthlike opening