Mountain Standard Time[mounˈtən]
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
a standard time used in the zone which includes the Rocky Mountain region of the U.S. corresponding to the mean solar time of the 105th meridian west of Greenwich, England: it is seven hours behind Greenwich time
Used by arrangement with John Wiley & Sons, Inc.
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.
noun Abbr. MST
Standard time in the seventh time zone west of Greenwich, England, reckoned at 105° west and used in the Rocky Mountain states of the United States. Also called Mountain Time.