plesiosaur

P3L1E1S1I1O1S1A1U1R1
/ˈpliːsiəsɔːɹ/

noun

Any of the order †Plesiosauria of extinct marine reptiles, from the Jurassic and Cretaceous periods.

First used c. 1840Scrabble 12

Meanings

nounplesiosaur (plural plesiosaurs)

plural plesiosaurs

  1. Any of the order †Plesiosauria of extinct marine reptiles, from the Jurassic and Cretaceous periods.First known use c. 1840

    It is the first time in Australia the head and body of an elasmosaur, a type of plesiosaur, has been found in one piece.

    2022 December 6, Rachael Merritt, “Australia's first complete plesiosaur fossil discovered in outback Queensland”, in ABC News
    1 more example

    "Look!" cried Olson. "Would you look at the giraffe comin' up out o' the bottom of the say?" We looked in the direction he pointed and saw a long, glossy neck surmounted by a small head rising above the surface of the river. Presently the back of the creature was exposed, brown and glossy as the water dripped from it. It turned its eyes upon us, opened its lizard-like mouth, emitted a shrill hiss and came for us. The thing must have been sixteen or eighteen feet in length and closely resembled pictures I had seen of restored plesiosaurs of the lower Jurassic.

    1918 September–November, Edgar Rice Burroughs, “The Land That Time Forgot”, in The Blue Book Magazine, Chicago, Ill.: Story-press Corp., →OCLC; republished as chapter IV, in Hugo Gernsback, editor, Amazing Stories, (please specify |part=I to III), New York, N.Y.: Experimenter Publishing, 1927, →OCLC

Synonyms & antonyms

nounextinct marine reptile with a small head on a long neck and a short tail and four paddle-shaped limbs; of the Jurassic and Cretaceous

Broader
archosaurarchosaurianarchosaurian reptile
Also see

Synonym sets from Open English WordNet, CC BY 4.0.

Origin

  1. translingualPlesiosaurus
  2. Englishplesiosaur

Backformation of translingual Plesiosaurus, named by William Conybeare and Henry De la Beche in 1824 because plesiosaurs were more like a normal reptile than Ichthyosaurus, which had been found in the same rock strata a few years earlier. Surface derivation, plesio- + -saur.

Full word history & related roots →

Translations

Chinese Mandarin 蛇頸龍 /蛇颈龙
  • 蛇頸龍 /蛇颈龙 (shéjǐnglóng)extinct marine reptile
Finnish joutsenlisko
  • joutsenliskoextinct marine reptile
French plésiosaure
  • plésiosaureextinct marine reptile
Icelandic svaneðla
  • svaneðlaextinct marine reptile
Italian plesiosauro
  • plesiosauroextinct marine reptile
Japanese 首長竜
  • 首長竜 (kubinagaryū)extinct marine reptile
Korean 수장룡
  • 수장룡 (sujangnyong)extinct marine reptile
Polish plezjozaur
  • plezjozaurextinct marine reptile
Portuguese plesiossauro
  • plesiossauroextinct marine reptile
Russian плезиоза́вр
  • плезиоза́вр (pleziozávr)extinct marine reptile
Spanish plesiosaurio
  • plesiosaurioextinct marine reptile
Swedish plesiosaurie, svanödla
  • plesiosaurieextinct marine reptile
  • svanödlaextinct marine reptile
Cite this entry
APA

plesiosaur. (n.d.). In WatkinsX Dictionary. Retrieved November 2, 2026, from https://dictionary.watkinsx.com/word/plesiosaur

MLA

“plesiosaur.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/plesiosaur. Accessed November 2, 2026.

Chicago

WatkinsX Dictionary, s.v. “plesiosaur,” accessed November 2, 2026, https://dictionary.watkinsx.com/word/plesiosaur.

Source: plesiosaur on Wiktionary, CC BY-SA 4.0.