plesiosaur n 1: 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}]
Plesiosaur \Ple"si*o*saur\, n. (Paleon.) One of the Plesiosauria. [1913 Webster]