'Plesiosauri' definitions:

Definition of 'Plesiosauri'

From: GCIDE

Plesiosaurus \Ple`si*o*sau"rus\, n.; pl. Plesiosauri. [NL., fr. Gr ? near + ? a lizard.] (Paleon.) A genus of large extinct marine reptiles, having a very long neck, a small head, and paddles for swimming. It lived in the Mesozoic age. [1913 Webster]