time zone

/ˌtaɪm ˈzoʊn/

/taɪm zəʊn/

Other forms: time zones

An area that officially synchronizes its clocks is a time zone. The U.S. is divided into 11 separate time zones.

If it's noon at your house in Vermont, it's still only 6 a.m. at your grandpa's place in Hawaii. That's because you live in two different time zones. This concept of dividing the entire world into separate zones is based on the sun's position in the sky. After railroads were invented, it became increasingly important to coordinate time between distant regions, which is how a standardized system for keeping track of the different zones came into being.

Definitions of time zone

1. noun

   any of the 24 regions of the globe (loosely divided by longitude) throughout which the same standard time is used
   type of:

   geographical zone, zone

   any of the regions of the surface of the Earth loosely divided according to latitude or longitude