This is a fun word…just the sound of it is pleasing, and its etymology interesting.

The English name for this large mammal found in the swamps, lakes, and waterways of sub-Saharan Africa comes, like several African animals, from ancient Greek.

The hippo segment, ἵππος in Greek, means “horse”. Several other words in English use this Greek word. One of my favorites is hippodrome, an arena for racing horses in ancient Greece. The word still retains this meaning today, but it has expanded to also occasionally refer to theaters or other entertainment venues. At such a race course, one might find many a hippomaniac! Such a lover of horses may experience increased activity in their hippocampus while watching horses run. The hippocampus is a component of the human brain, thought to resemble the shape of a seahorse. It is considered part of the limbic system and is involved with emotions and the recording of new memories, among other functions.

I think the second part, potamus, is particularly interesting in its connection to other words used in English. Potamus (ποταμός in Greek) means “river”, so that hippopotamus means “river-horse”. While not as gracile as a horse, it’s a fairly apt description of this semi-aquatic quadruped.

Potamus leads to some other really fun words. Mesopotamia, the land between the Euphrates and Tigris, is quite literally “between rivers” (and makes me think of Mesoamerica, the land “between the Americas”).

Potable, as in water safe to drink, is another word downstream of potamus (pun intended), as are a number of more obscure words, such as tychopotamic, eupotamic, and potamium. A potamophile might be familiar with some of these more esoteric words, most of which are used in scientific contexts.