1.NounAny of the clade †Stegosauria of quadruped ornithischian dinosaurs with dorsal plates and spikes, alive during the Jurassic and early Cretaceous periods.
2.NounAny of the genus †Stegosaurus of herbivorous four-legged armored dinosaurs from the Late Jurassic, characterized by the distinctive kite-shaped upright plates along their backs and spikes on their tails.