Why is a hippopotamus called a hippopotamus?

Answer 1

"Hippo" is a shortened form of the word hippopotamus, which comes from the Greek words for River Horse. It's a suitable name because the African animal spends a great deal of time in the water and it looks like a horse with its large ears and nostrils.

Answer 2

The word hippopotamus literally means "riverine horse" in the original Greek. "Hippos" means "horse" and "potamios" means "river" or "rushing water".

Answer 3

Because they both descended from the same ancestors. Pleohippus maybe? But scientific names for horses and their ancestors have the prefix 'hippus'.