Time zone
Fuseau horaire | タイムゾーン | 时区
Pocket watche with 2 movements giving 2 local times - Musée de l'horlogerie du Locle
In order to standardise time measurement in each country, since 1883 the Earth has been divided into twenty-four time zones, the first of which is intersected by the Greenwich meridian, which is the prime or zero meridian. Each point within a given time zone has the same legal time.