Real Dictionary

reptile
countable noun: Reptiles are a group of cold-blooded animals which have skins covered with small hard plates called scales and lay eggs. Snakes, lizards, and crocodiles are reptiles.

reptile in American English
any of a class (Reptilia) of coldblooded vertebrates having lungs, an entirely bony skeleton, a body covered with scales or horny plates, and a heart with two atria and, usually, a single ventricle, including the snakes, lizards, turtles, crocodiles, and
of, like, or characteristic of a reptile; reptilian
adjective: of or resembling a reptile; creeping or crawling
noun: any cold-blooded vertebrate of the class Reptilia, comprising the turtles, snakes, lizards, crocodilians, amphisbaenians, tuatara, and various extinct members including the dinosaurs

reptile in British English
adjective: creeping, crawling, or squirming
noun: any of the cold-blooded vertebrates constituting the class Reptilia, characterized by lungs, an outer covering of horny scales or plates, and young produced in amniotic eggs. The class today includes the tortoises, turtles, snakes, lizards, and crocodiles