|tyrannosaur (tĭ-rān'ə-sôr') Pronunciation Key
Any of various very large carnivorous dinosaurs of the genus Tyrannosaurus and related genera of the Cretaceous Period. Tyrannosaurs had very small forelimbs and a large head with sharp teeth. They walked on two legs, probably bent forward with their long tail stretched out as a counterbalance. Tyrannosaurs were theropods and probably distantly related to birds. The largest species, T. rex, grew to lengths of 14.3 m (47 ft) or more and may have been the largest land predator that ever lived.