/ Dictionary / Index A archosaur: Meaning and Definition of Find definitions for: ar•cho•saur Pronunciation: (är'ku-sôr"), [key] — n. any reptile of the subclass Archosauria, including the dinosaurs, pterosaurs, and crocodilians and characterized by two pairs of openings in the temporal region of the skull. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: archosaur (Thesaurus) archon archpriest Related Content Daily Word Quiz: exemplary Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language