MST

from WordNet (r) 3.0 (2006)

MST
    n 1: standard time in the 7th time zone west of Greenwich,
         reckoned at the 105th meridian west; used in the mountain
         states of the United States [syn: {Mountain Time},
         {Mountain Standard Time}, {MST}]

from The Collaborative International Dictionary of English v.0.48

MST \MST\ n.
   Mountain Standard Time, the time of the 105th meridian, used
   in the mountain states of the U.S. [abbr.]

   Syn: Mountain Time, Mountain Standard Time.
        [WordNet 1.5]

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

MST
       Mountain Standard Time [-0700] (TZ, MDT, USA)

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