tyrannosaurus(n = noun.animal) tyrannosaur, tyrannosaurus rex - large carnivorous bipedal dinosaur having enormous teeth with knifelike serrations; may have been a scavenger rather than an active predator; later Cretaceous period in North America;
tyrannosaurus, n. (also tyrannosaur) any bipedal flesh-eating dinosaur of the genus Tyrannosaurus, esp. T. rex having powerful hind legs, small clawlike front legs, and a long well-developed tail.