centrum vs os

centrum and os both are nouns.

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

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

Other hypernyms of centrum include bone.

centrum (noun)	os (noun)
the main body of a vertebra	rigid connective tissue that makes up the skeleton of vertebrates
	a mouth or mouthlike opening