The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
A volcano, 5,455.5 m (17,887 ft) high, in central Mexico west of Puebla. It became active again in January 1994 after being dormant for decades.