Pronunciation: (dī-ap'sid), [key]
(of reptiles) having two openings in the skull behind each eye, characteristic of the subclasses Lepidosauria and Archosauria, including all living reptiles except turtles.
a diapsid reptile. Cf. anapsid.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.