cer·a·top·si·an 
(sĕr′ə-tŏpsē-ən)
(sĕr′ə-tŏpsē-ən)n.
Any of various herbivorous quadrupedal ornithischian dinosaurs of the group Ceratopsia of the Cretaceous Period, having a beaked mouth, usually a bony frill on the back of the skull, and sometimes horns.
[From New Latin Cerātōpsia, suborder name : Greek keras, kerāt-, horn; see ker-1 in the Appendix of Indo-European roots + Greek ōps, eye, face; see okw- in the Appendix of Indo-European roots.]
cer′a·topsi·an adj.