The DICT Development Group

  universal time
      n 1: the local time at the 0 meridian passing through Greenwich,
           England; it is the same everywhere [syn: Greenwich Mean
           Time, Greenwich Time, GMT, universal time, UT,
           UT1]

  Universal Time
  
      (UT) The mean solar time along the prime
     meridian (0 longitude) that runs through the Greenwich
     Observatory outside of London, UK, where the current system
     originated.  UT is tied to the rotation of the Earth in
     respect to the fictitious "mean Sun".
  
     Greenwich Mean Time (GMT) was measured from Greenwich mean
     midday until 1925 when the reference point was changed from
     noon to midnight and the name changed to "Universal Time".
  
     There are three separate definitions, UT0, UT1, and UT2,
     depending on which corrections have been applied to the
     Earth's motion.  Coordinated Universal Time is kept within
     0.9 seconds of UT1, by addition of leap seconds to
     International Atomic Time.
  
     (2001-08-02)