Webster’s Revised Unabridged Dictionary · 1913
Ichthyosaurus
Ich′thy·o·sau′rus (·sa̤′rŭs), n.; pl. Ichthyosauri (#). [NL., fr. Gr. ἰχθύς, -ύος, a fish + σαῦρος a lizard.] (Paleon.) An extinct genus of marine reptiles; - - so named from their short, biconcave vertebræ, resembling those of fishes. Several species, varying in length from ten to thirty feet, are known from the Liassic, Oölitic, and Cretaceous formations.