Dictionary
pel•y•co•saur
Pronunciation: (pel'i-ku-sôr"), [key]—
n.
any of a group of large primitive reptiles belonging to the extinct order Pelycosauria, abundant in North America and Europe during the Permian Period, often having a tall spinal sail.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.