PLESIOSAUR
Ple"si*o*saur, n. (Paleon.)
Defn: One of the Plesiosauria.
PLESIOSAURIA
Ple`si*o*sau"ri*a, n. pl. Etym: [NL. See Plesiosaurus.] (Paleon.)
Defn: An extinct order of Mesozoic marine reptiles including the genera Plesiosaurus, and allied forms; — called also Sauropterygia.
PLESIOSAURIAN
Ple`si*o*sau"ri*an, n. (Paleon.)
Defn: A plesiosaur.
PLESIOSAURUS
Ple`si*o*sau"rus, n.; pl. Plesiosauri. Etym: [NL., fr. Gr (Paleon.)
Defn: 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.
PLESSIMETER
Ples*sim"e*ter, n.
Defn: See Pleximeter.