A hippopotamus is a very large, heavy, grey animal from Africa. It has a wide head, small ears, short legs, and a mouth that can open hugely. It lives in and beside rivers and lakes; on a hot day you may see only the eyes and nose above the water. It eats plants, mostly at night when it comes onto the land. In easy talk people say hippo — same animal, shorter word. It looks slow and calm in the water, though actually it can move fast and it can bite; it is not a soft zoo toy in the wild. The name comes from Greek for river horse, which is a picture in the mind, not a family fact: it is not a horse. English once said river horse, and had an old native word nicker; hippopotamus pushed those aside from the 1500s. The everyday plural is hippopotamuses. Some people say hippopotami; that sounds more Latin and a little proud of itself.