plesiosaur

American  

[plee-see-uh-sawr] / ˈpli si əˌsɔr /

noun

1. any marine reptile of the extinct genus Plesiosaurus, from the Jurassic and Cretaceous periods, having a small head, a long neck, four paddlelike limbs, and a short tail.

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plesiosaur British  

/ ˈpliːsɪəˌsɔː /

noun

1. any of various extinct marine reptiles of the order Sauropterygia, esp any of the suborder Plesiosauria, of Jurassic and Cretaceous times, having a long neck, short tail, and paddle-like limbs See also ichthyosaur Compare dinosaur pterosaur

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plesiosaur Scientific  

/ plē′sē-ə-sôr′ /

1. Any of various large, extinct marine reptiles of the genus Plesiosaurus and related genera of the Mesozoic Era. Most plesiosaurs had a small head on a long neck and a broad body with paddlelike limbs; one group had a large head on a short neck. The exact relationship between plesiosaurs and other reptiles is not known.

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Other Word Forms

Derived Forms

• plesiosauroid
  adjective

Etymology

Origin of plesiosaur

< New Latin Plesiosaurus (1821), equivalent to Greek plēsí ( os ) near, close to + -o- -o- + saûros -saur; originally so named because of its conjectured nearness to modern reptiles, relative to the ichthyosaurs

Example Sentences

His first thoughts were that it might be another marine reptile like an ichthyosaur or plesiosaur.

From BBC • Apr. 22, 2026

Pliosaurs were a type of plesiosaur with short necks and massive skulls.

From Science Daily • Oct. 20, 2023

The 11-foot-long plesiosaur was discovered in the 1990s in Gloucestershire, England and is believed to have lived about 190 million years ago.

From Seattle Times • Jul. 11, 2023

A 100-million-year-old plesiosaur fossil has been found by a group of friends in the Australian outback.

From BBC • Dec. 7, 2022

Those weren’t the regular harbor lights; they were the twin lanterns of the plesiosaur artillery units.

From "Dactyl Hill Squad" by Daniel José Older