CORDILLERA, a Spanish term for a range or chain of mountains, derived from the Old Spanish cordilla, the diminutive of cuerda, a cord or rope. The name was first given to the Andes ranges of South America, Las Cordilleras de los Andes, and applied to the extension of the system into Mexico. In North America the parallel ranges of mountains running between and including the Rocky Mountains and the Sierra Nevada are known as the “Cordilleras,” and that part of the western continent crossed by them has been termed the “Cordilleran region.” Although the name has been applied to the eastern mountain system of Australia, the word is not, outside America, used as a generic term for parallel ranges of mountains.