platypus

American  

[plat-i-puhs, -poos] / ˈplæt ɪ pəs, -ˌpʊs /

noun

• platypuses,
  plural
• platypi
  plural

1. a small, aquatic, egg-laying monotreme, Ornithorhynchus anatinus, of Australia and Tasmania, having webbed feet, a tail like that of a beaver, a sensitive bill resembling that of a duck, and, in adult males, venom-injecting spurs on the ankles of the hind limbs, used primarily for fighting with other males during the breeding season.

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platypus British  

/ ˈplætɪpəs /

noun

1. See duck-billed platypus

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Usage

Plural word for platypus The plural form of platypus can be either platypuses or platypi, pronounced [ plat-i-pahy ], but platypuses is more widely used. The plurals of several other singular words ending in -us are formed in the same way as platypuses, such as virus/viruses, sinus/sinuses, and walrus/walruses. Irregular plurals that are formed like platypi, 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

Noun Inflected Forms

• platypi
  plural
• platypuses
  plural

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Etymology

Origin of platypus

1790–1800; < New Latin < Greek platýpous flat-footed, equivalent to platy- platy- + -pous, adj. derivative of poús foot

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Explanation

What animal has a duck bill, fuzzy kitten belly, beaver tail, and poisonous webbed feet? A platypus! A platypus is a wacky mammal that mainly lives in the water off Australia. Although a platypus is a mammal, it lays eggs. Because of its distinctive bill, the platypus is often called the duck billed platypus. It's an unusual animal, defying many of the usual characteristics of a mammal — the platypus lays eggs, is aquatic, has a tail like a beaver's, is venomous like a snake, and has feet like an otter. In fact, when scientists from Europe first discovered the platypus, many of them thought it was a hoax. The Greek root, platypous, means "flat-footed."

Example Sentences

See Examples For:

platypus platypuses

"They spent a lot of time on land, like a modern-day alligator or platypus does," Gordon said.

From Science Daily ● Oct. 25, 2026

Most modern mammals reproduce by giving birth, but a few species, such as the platypus, still retain the older egg-laying trait.

From Science Daily ● May 1, 2026

While this purse string model applies broadly, it does not explain division in species with especially large embryonic cells, including sharks, platypus, birds and reptiles.

From Science Daily ● Feb. 28, 2026

"It was so obvious that, but for the misfortunes of war, a fine, thriving, healthy little platypus would have created history in being number one of its kind to take up residence in England."

From BBC ● Aug. 2, 2025

They’d faced many scary things, but nothing like a bendy man, giant platypus, or frozen time.

From "The Last Last-Day-of-Summer" by Lamar Giles

Its ecosystem included frogs, lizards, turtles, and mammals such as Patagorhynchus pascuali, a semi aquatic monotreme related to modern echidnas and platypuses.

From Science Daily ● May 29, 2026

Even as far back as the 1940s, people knew that platypuses were voracious eaters.

From BBC ● Aug. 2, 2025

Like chickens, duck-billed platypuses, and other animals that hatch from eggs, you had a yolk sac when you were an embryo.

From Science Magazine ● Aug. 16, 2023

In his view, along with climate change and platypuses accidentally drowned in fishing nets, dams are one of most significant threats to the animals’ survival.

From New York Times ● Nov. 4, 2022

Augustus and I were together in the Improbable Creatures Club: us and duck-billed platypuses.

From "The Fault in Our Stars" by John Green

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