from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of various very large extinct aquatic lizards of the genus Mosasaurus, having modified limbs that served as paddles for swimming. These lizards, thought to have been viviparous and carnivorous, may be early ancestors of the modern monitor lizard.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An large extinct marine reptile, in the family Mosasauridae; the ancestor of modern snakes.
from the GNU version of the Collaborative International Dictionary of English
- n. One of an extinct order of reptiles, including Mosasaurus and allied genera. See mosasauria.
from The Century Dictionary and Cyclopedia
- n. A general name for the large, extinct marine reptiles of the family Mosasauridæ, including the well-known genera Mosasaurus, Tylosaurus, Clidastes, etc. They had long, pointed heads, rather long bodies, a compressed tail, and limbs modified into short, flattened paddles. They abounded in the Cretaceous period and their remains are particularly abundant in the chalk of Kansas.
New Latin Mosasaurus, genus name : Latin Mosa, the Meuse River (where fossils of the genus were first discovered) + Greek sauros, lizard.(American Heritage® Dictionary of the English Language, Fourth Edition)