water ox vs carabao

water ox and carabao both are nouns.

Word	Noun	Adjective	Verb	Adverb
water ox	Yes	No	No	No
carabao	Yes	No	No	No

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

water ox: an Asian buffalo that is often domesticated for use as a draft animal
carabao: water buffalo of the Philippines

Other hyponyms of water ox include Indian buffalo.

water ox (noun)	carabao (noun)
an Asian buffalo that is often domesticated for use as a draft animal	water buffalo of the Philippines