Stegosaur

noun
1.
a plant-eating dinosaur of the genus Stegosaurus, from the Jurassic and Cretaceous periods, having a heavy, bony armor and a row of bony plates along its back, and growing to a length of 20 to 40 feet (6–12 meters).
noun
1.
any quadrupedal herbivorous ornithischian dinosaur of the suborder Stegosauria, esp any of the genus Stegosaurus, of Jurassic and early Cretaceous times, having an armour of bony plates
stegosaur
(stěg’ə-sôr’)
Any of several large herbivorous ornithischian dinosaurs of the group Stegosauria of the Jurassic and early Cretaceous Periods. The largest genus, Stegosaurus, had a tail with two horizontal spikes for defense, and an arched back with an alternating double row of large, triangular, upright bony plates. Stegosaurs grew over 6 m (20 ft) long, but had extremely small heads with brains the size of a walnut. The hindquarters were controlled by a neural ganglion in the hip region that was larger than the brain.