1) Bird-footed dinosaur 2) Ceratosaurus 3) Theropod 4) Theropod dinosaur 1) Ceratosaurus 2) Coelophysis 
[n] - primitive medium-sized theropod
ceratosaurus noun primitive medium-sized theropod; swift-running bipedal carnivorous dinosaur having grasping hands with sharp claws and a short horn between the nostrils; Jurassic in North America
a carnivorous, swift-running North American theropod dinosaur of the genus Ceratosaurus and closely related genera, of the Jurassic Period, having a large skull with a short horn between the nostrils and a bony knob in front of each eye, and reaching a length of 20 ft. (6.1 m).