Definition of opisthocoelian in English:

opisthocoelian

Pronunciation /ə(ʊ)ˌpɪsθəˈsiːlɪən/

adjective

rare Zoology

Origin

Mid 19th century; earliest use found in Richard Owen (1804–1892), comparative anatomist and palaeontologist. From opistho- + ancient Greek κοῖλος hollow + -ian.