ox vs Bos primigenius

ox and Bos primigenius both are nouns.

Word	Noun	Adjective	Verb	Adverb
ox	Yes	No	No	No
Bos primigenius	Yes	No	No	No

As nouns, Bos primigenius is a hyponym of ox; that is, Bos primigenius is a word with a more specific, narrower meaning than ox:

ox: any of various wild bovines especially of the genera Bos or closely related Bibos
Bos primigenius: large recently extinct long-horned European wild ox; considered one of the ancestors of domestic cattle

Other hyponyms of ox include aurochs, urus, Bos grunniens, yak, banteng, banting, Bos banteng, tsine, Asian wild ox.

ox (noun)	Bos primigenius (noun)
any of various wild bovines especially of the genera Bos or closely related Bibos	large recently extinct long-horned European wild ox; considered one of the ancestors of domestic cattle
an adult castrated bull of the genus Bos; especially Bos taurus