Laopteryx is the name assigned to a pterosaur (flying reptile) from the Upper Jurassic Morrison Formation of Wyoming, United States; it was originally thought to be a bird. The genus was named in 1881 by Othniel Charles Marsh. The generic name is derived from Greek laas, "stone", and pteryx, "wing". The full species name given by Marsh was Laopteryx priscum; the specific name meaning "of venerable age" in Latin. However, Marsh incorrectly used the neuter form, while pteryx is feminine in Greek. (See grammatical gender.) This was in the 19th century emended to an, also incorrect, masculine priscus and in 1971 by Pierce Brodkorb to prisca.