'Plesiosaur' definitions:

Definition of 'plesiosaur'

From: WordNet
noun
Extinct marine reptile with a small head on a long neck a short tail and four paddle-shaped limbs; of the Jurassic and Cretaceous [syn: plesiosaur, plesiosaurus]

Definition of 'Plesiosaur'

From: GCIDE
  • Plesiosaur \Ple"si*o*saur\, n. (Paleon.) One of the Plesiosauria. [1913 Webster]