- the civil time officially adopted for a country or region, usually the civil time of some specific meridian lying within the region. The standard time zones in the United States (Atlantic time, Eastern time, Central time, Mountain time, Pacific time, Yukon time, Alaska-Hawaii time, and Bering time ) use the civil times of the 60th, 75th, 90th, 105th, 120th, 135th, 150th, and 165th meridians respectively, the difference of time between one zone and the next being exactly one hour.
- the official local time of a region or country determined by the distance from Greenwich of a line of longitude passing through the area
