Original: Gorgosaurus (, meaning "fierce lizard") is a genus of tyrannosaurid theropod dinosaur that lived in western North America during the Late Cretaceous Period, between about 76.5 and 75 million years ago.
Simplified: Gorgosaurus is a genus of theropod dinosaur that lived in western North America during the Upper Cretaceous, between about 76.5 and 75 million years ago.