Eastern time

noun

• 1the standard time in a zone including the eastern states of the US and parts of Canada, specifically:

  • (Eastern Standard Time, abbreviation: EST) standard time based on the mean solar time at the meridian 75° W, five hours behind GMT. (Eastern Daylight Time, abbreviation: EDT) Eastern time during daylight saving time, four hours behind GMT.

• 2the standard time in a zone including eastern Australia, based on the mean solar time at the meridian 150° E. It is ten hours ahead of GMT, or nine hours ahead when summer time is observed.