What does "hippopotamus" mean and in what langauge?

The story behind the answer

“Hippopotamus” comes from Greek: hippos = horse and potamos = river, so it literally means “river horse.” The name fits their lifestyle—hippos spend most of the day in rivers and lakes to stay cool, then graze on land at night.

Memory tips: potamos also appears in “Mesopotamia,” meaning “land between rivers,” and hippo shows up in “hippocampus,” a