Standard time, time kept in the time zones of the world. In the United States the zones are called Eastern, Central, Mountain, and Pacific. The standard time in each zone lags Greenwich mean time (GMT) by 5, 6, 7, and 8 hours respectively. Standard time in Hawaii and Alaska is 10 hours behind GMT. The zones depend on the fact that the earth takes an hour to rotate 15°. Therefore the sun rises an hour later for every 15° west. Each time zone is roughly centered on a meridian (line of longitude) 15° farther west than its predecessor.
See also: Fleming, Sir Sandford.