In a Word: Putting the ‘Horse’ in ‘Hippopotamus’

Managing editor and logophile Andy Hollandbeck reveals the sometimes surprising roots of common English words and phrases. Remember: Etymology tells us where a word comes from, but not what it means today.

You might think that someone suffering from hippophobia has a debilitating fear of hippopotamuses. But that isn’t the case. The hippo- part hippophobia comes from Greek word hippos “horse” — hippophobia is a fear of horses.

The name for the third largest land animal on the planet comes from the Greek hippos potamios, meaning “river horse,” borrowed into Latin and eventually becoming, by the mid-16th century, hippopotamus. It’s a good descriptive name: It’s got four legs, like a horse, and it spends up to 16 hours a day in the water to keep its hide from drying out.

Don’t even dream of strapping a saddle on one of these big beasts and riding off into the African sunset, though; genetically, hippos are more closely related to pigs and whales than to horses, and according to the National Wildlife Federation, they kill about 3,000 people a year. Best to admire them from a distance.

That leaves us with one question: If hippophobia is a fear of horses, what word describes a debilitating fear of hippopotamuses? If the need ever arose to diagnose such a condition, hippopotamophobia is the likeliest candidate.

About the plural: Hippopotamus didn’t enter English directly from the Greek, but was first borrowed into Latin; therefore, the Latin plural form hippopotami is acceptable. But because hippopotamus is an English word, standard English pluralization rules can be applied to it as well, so hippopotamuses is also an acceptable — and often preferred — plural.