these two abbreviations means Greenwich Mean Time and Coordinated Universal Time (CUT)
UTC was the first reference for the world to maintain a constant time in the years about 1960 according to this wiki-Related-Page .
there is a difference between UTC , TUC and CUT .
the TUC (temps universel coordonné) is the french equal of CUT or TCU
according to the above image , you can calculate any location's time difference .
for example ARABIA is 3 hours ahead of the UTC and Iran is 4 hours and 30 minutes ahead of Coordinated Universal time.
time the GMT is the current time of the city Greenwich located in England.
