ceratopsian
Concise Oxford English Dictionary © 2008 Oxford University Press:
ceratopsian /ˌsɛrəˈtɒpsɪən, ˌkɛr-/
▶noun Palaeontology a gregarious quadrupedal herbivorous dinosaur of a group including triceratops, with a bony frill protecting the neck.
– origin early 20th cent.: from mod. L. Ceratopsia (pl., from Gk keras, kerat- ‘horn’ + ops ‘face’) + -an.
'ceratopsian' also found in these Oxford entries:

