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

Etymology

Origin of platypus

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

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

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

Some of the bones belonged to the already-discovered Steropodon galmani, a shorter, stumpier and toothier ancestor of the platypus.

From BBC ● May 27, 2024

Bjorkstrand may have led Columbus in goals for two consecutive years before coming to Seattle, but this was like being the world’s prettiest platypus.

From Seattle Times ● May 1, 2024

Otto knew deep down the word platypus wasn’t exactly right.

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

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

But they are also concerned about the safety of the two people, as platypuses have a venomous spur that can cause serious injury.

From BBC ● Apr. 5, 2023

Adult platypuses are toothless, chewing their food with pads made of keratin, fibrous proteins similar to those found in human fingernails and hair.

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