[ ˌɔ:nɪ'θɪskɪən , -'θɪʃɪən ]
■ noun Palaeontology a herbivorous dinosaur of a group with a pelvic structure resembling that of birds. Compare with saurischian .
Origin
C19: from mod. L. Ornithischia (name of an order), from Gk ornis , ornith- 'bird' + iskhion 'hip joint'.