1) Pachycephalosaurus 
(from the article `dinosaur`) In important respects the pachycephalosaurs conformed to the basic ornithopod body plan, and there is some evidence that pachycephalosaurs actually ... The ornithischians can be divided into two distinct subgroups: Cerapoda and Thyreophora. The cerapods are further subdivided into the Ornithopoda, ... [2...
[n] - bipedal herbivore having 10 inches of bone atop its head
Pachycephalosaurus, Pachycephalosaur A “thick-headed lizard” from Late Cretaceous Montana. Named by paleontologist Barnum Brown (1873-1963) and Schlaikjer in 1943.
pachycephalosaurus noun bipedal herbivore having 10 inches of bone atop its head; largest boneheaded dinosaur ever found