Definition of Plesiosaurus in US English:

Plesiosaurus

noun

  • A genus of extinct marine reptiles of the infraorder Plesiosauria, having a small head on a long neck, a short tail, and four large paddle-like limbs; (also plesiosaurus) a reptile of this genus.

Origin

Early 19th century. From scientific Latin Plesiosaurus from plesio- + ancient Greek σαῦρος lizard.

Pronunciation

Plesiosaurus

/ˌpliːzɪəˈsɔːrəs/