/ Dictionary / Index P pelycosaur: Meaning and Definition of Find definitions for: 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. See also: pelycosaur (Thesaurus) pelvis Pematangsiantar Related Content Daily Word Quiz: supine Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language