| Noun | 1. | corythosaurus - duck-billed dinosaur with nasal passages that expand into a crest like a hollow helmetduck-billed dinosaur, hadrosaur, hadrosaurus - any of numerous large bipedal ornithischian dinosaurs having a horny duck-like bill and webbed feet; may have been partly aquatic genus Corythosaurus - genus of duck-billed dinosaurs of late Cretaceous |