hippopotamus

American  

[hip-uh-pot-uh-muhs] / ˌhɪp əˈpɒt ə məs /

noun

plural

hippopotamuses, hippopotami

1. a large herbivorous mammal, Hippopotamus amphibius, having a thick hairless body, short legs, and a large head and muzzle, found in and near the rivers, lakes, etc., of Africa, and able to remain under water for a considerable time.

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hippopotamus British  

/ ˌhɪpəˈpɒtəməs /

noun

1. a very large massive gregarious artiodactyl mammal, Hippopotamus amphibius, living in or around the rivers of tropical Africa: family Hippopotamidae. It has short legs and a thick skin sparsely covered with hair

2. a related but smaller animal, Choeropsis liberiensis

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Usage

Plural word for hippopotamus The plural form of hippopotamus can be either hippopotamuses or hippopotami. Hippopotamuses is more widely used. The plurals of several other singular words ending in -us are also formed this way, such as virus/viruses, sinus/sinuses, and walrus/walruses. Irregular plurals that are formed like hippopotami, such as cactus/cacti and fungus/fungi, derive directly from their original pluralization in Latin. However, the standard English plural -es ending is often also acceptable for these terms, as in cactuses.

Other Word Forms

• hippopotamian adjective
• hippopotamic adjective

Etymology

Origin of hippopotamus

1555–65; < Latin < Greek hippopótamos, earlier híppos potámios literally, riverine horse (term used by Herodotus in his account of the Egyptian hippopotamus); compare Middle English ypotame, ypotamos, ypotanus < Old French ypotame < Medieval Latin ypotamus

Explanation

A hippopotamus is a huge African mammal that spends time in the water and on land. These herbivores are so enormous that one hippopotamus can eat two pounds of grass in a single feeding. Although they're plant-eaters, hippopotamuses are powerfully strong and fiercely protective. Experts consider them to be unpredictable as well, and if you happen to be in sub-saharan Africa, it's smart to keep your distance! Hippopotamus is from the Greek ho hippos potamios, "the horse of the river," and its roots, hippos, "horse," and potamos, "rushing water."

Example Sentences

A $31.4 million bar cart shaped like a hippopotamus.

From The Wall Street Journal • Dec. 17, 2025

Researchers examined numerous hippopotamus fossils using both genetic and radiocarbon dating methods.

From Science Daily • Oct. 26, 2025

An "incredibly rare" female baby hippopotamus has been born at Edinburgh Zoo.

From BBC • Nov. 5, 2024

While not much is known about hippopotamus intelligence, a 2022 study in the journal Science found that hippos can recognize the voices of their friends and potential enemies.

From Salon • Aug. 30, 2024

As well picture a block of granite wafting like a feather, or a hippopotamus slithering like a cat.

From "The Golden Goblet" by Eloise Jarvis McGraw