Standard time Meaning, Definition & Usage

  1. noun the official time in a local region (adjusted for location around the Earth); established by law or custom
    civil time; local time.

WordNet

Definitions
  1. the civil time that has been established by law or by general usage over a region or country. In England the standard time is Greenwich mean solar time. In the United States and Canada four kinds of standard time have been adopted by the railroads and accepted by the people, viz., Eastern, Central, Mountain, and Pacific time, corresponding severally to the mean local times of the 75th, 90th, 105th, and 120th meridians west from Greenwich, and being therefore five, six, seven, and eight hours slower than Greenwich time.

Webster 1913