[ ahr-kuh-sawr ]
/ ˈɑr kəˌsɔr /


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.

Origin of archosaur

1965–70; < New Latin Archosaurus, taken as singular of Archosauria, equivalent to Greek archo-, combining form of archós ruler, chief + saûr(os) -saur + New Latin -ia -ia

Related forms

ar·cho·sau·ri·an, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Science definitions for archosaur


[ ärkə-sôr′ ]

Any of various mostly reptilian animals of the subclass Archosauria. Archosaurs are diapsids that began to evolve in the late Permian Period, and are characterized by skulls with long, narrow snouts and teeth set in sockets. Archosaurs include the extinct dinosaurs and pterosaurs and the modern crocodilians and birds.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.