: a class of Vertebrata comprising air-breathing animals that have lungs but never gills, usually a three-chambered heart, two aortic arches from which the systemic arteries arise, a bony skeleton in which the skull articulates with the vertebral column by a single occipital condyle, the vertebrae gastrocentral, and the compound mandible articulate with the skull through a quadrate bone, that lack hair or feathers and have the skin more or less covered with horny epidermal plates or scales and relatively free from glands, that are known since the Carboniferous and as the dominant form of life in the Mesozoic, and that are represented in the recent fauna by the snakes and lizards, the turtles, the loricates, and the aberrant tuatara see cotylosauria , loricata , mesosauria , pelycosauria , pterosauria , rhynchocephalia, squamata , testudinata , therapsida
Word History
Etymology
New Latin, from Late Latin, plural of reptile
The Ultimate Dictionary Awaits
Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.
Expanded definitions
Detailed etymologies
Advanced search tools
All ad-free
Discover what makes Merriam-Webster Unabridged the essential choice
for true word lovers.
Share