Mean Time, or GMT (also called Universal Time, or UT):
international time-keeping standard based on the local time in Greenwich,
England (0 degrees longitude). GMT (UT) enables us to refer to things
that happen at the same moment in different time zones. (It would
be confusing to use "local time.") At any moment, GMT is
the same everywhere on earth. (That's why it's also called universal
time.) What time is it now? Check the Greenwich
Mean Time clock.
map shows how many hours you need to add to or subtract from your local
time to get the GMT.