Aurochs and Ox

Aurochs noun - Large recently extinct long-horned European wild ox; considered one of the ancestors of domestic cattle.

Ox and aurochs are semantically related. In some cases you can use "Ox" instead a noun "Aurochs".

Ox noun - Any of various wild bovines especially of the genera Bos or closely related Bibos.

Aurochs and ox are semantically related. Sometimes you can replace term "Aurochs" with "Ox", this nouns are similar.