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

• 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

Meals would have included other reptiles such as its long-necked cousin, the plesiosaur, and the dolphin-like ichthyosaur - and fossil evidence reveals that it would have even feasted on other passing pliosaurs.

From BBC • Dec. 10, 2023

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

From Science Daily • Oct. 20, 2023

Numerous theories or explanations have been put forward over the years, including that the creature may have been a plesiosaur, a prehistoric marine reptile, giant eels or even swimming circus elephants.

From Seattle Times • Aug. 5, 2023

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