plesiosaur

American

[plee-see-uh-sawr] / ˈpli si əˌsɔr /

noun

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.

plesiosaur British

/ ˈpliːsɪəˌsɔː /

noun

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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

plesiosaur Scientific

/ plē′sē-ə-sôr′ /

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.

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

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

plesiosaur

His colleague then looked over his shoulder at what he was holding and said, "either plesiosaur or croc."

From BBC ● Apr. 22, 2026

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

From Science Daily ● Oct. 20, 2023

However, the discovery of the plesiosaur bone was "remarkable", the team said.

From BBC ● Aug. 22, 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

Up ahead, the plesiosaur riders were probably readying their artillery, or simply loading their muskets to enfilade them as soon as they were in range.

From "Dactyl Hill Squad" by Daniel José Older

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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023