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

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

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

Water Lily, a 45-year-old female hippopotamus who has lived at the Woodland Park Zoo since 1979, will be euthanized next week.

From Seattle Times • Apr. 26, 2024

All six-thousand hippopotamus pounds of Fry dive for my ankles.

From "I'll Give You the Sun" by Jandy Nelson