The Collaborative International Dictionary
Platycoelian
Platycoelian \Plat`y*c[oe]"li*an\, a. [Platy + Gr. ? hollow.] (Anat.) Flat at the anterior and concave at the posterior end; -- said of the centra of the vertebr[ae] of some extinct dinouaurs.
Wiktionary
platycoelian
a. (context anatomy English) Flat at the anterior and concave at the posterior end; said of the centra of the vertebrae of some dinosaurs.