time zone science definition

Any of the 24 divisions of the Earth's surface used to determine the local time for any given locality. Each zone is roughly 15° of longitude in width, with local variations for economic and political convenience. Local time is one hour ahead for each time zone as one travels east and one hour behind for each time zone as one travels west. The International Meridian Conference in 1884 established the prime meridian  as the starting point for the 24 zones. See more at International Date Line, standard time.