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

Inflected Forms

noun

• platypuses
  plural
• platypi
  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

Today, Kanekar is the founder of Platypus Technologies, which provides advisory services to organizations looking to establish an FDE team.

From MarketWatch • Apr. 4, 2026

Platypus doesn’t hold a stake in either stock.

From The Wall Street Journal • Jan. 9, 2026

“He could do anything, build anything. He was a tough guy himself,” Young said during an interview with visual production company Platinum Platypus.

From Los Angeles Times • Oct. 19, 2023

Platypus are found all along eastern Australia, in freshwater creeks, slow-moving rivers, lakes and dams.

From BBC • Apr. 5, 2023

Duck′-ant, a Jamaican termite nesting in trees; Duck′-bill, an aquatic burrowing and egg-laying Australian mammal, about 18 inches long, with soft fur, broadly webbed feet, and depressed duck-like bill—also called Duck-mole, Platypus, and Ornithorhynchus.—adj.

From Chambers's Twentieth Century Dictionary (part 1 of 4: A-D) by Various