In fact, the animal's name means "king of the tyrant lizards". "Tyranno" means tyrant in Greek; "saurus" means lizard in Greek; and "rex" translates to "king" in Latin. In 1905, Henry Fairfield Osborn, president of the American Museum of Natural History at the time, officially dubbed the species Tyrannosaurus rex.

T. rex was a member of the Tyrannosauroidea family of huge predatory dinosaurs with small arms and two-fingered hands. Aside from Tyrannosaurs, other Tyrannosaurid genera include Albertosaurus, Alectrosaurus, Alioramus, Chingkankousaurus, Daspletosaurus, Eotyrannus, Gorgosaurus, Nanotyrannus (a controversial genus that experts say is likely an adolescent T. rex), Prodeinodon, Tarbosaurus and Zhuchengtyrannus. -Noodle913