<P> Coordinated Universal Time (abbreviated to UTC) is the primary time standard by which the world regulates clocks and time . It is within about 1 second of mean solar time at 0 ° longitude; it does not observe daylight saving time . For most purposes, UTC is considered interchangeable with Greenwich Mean Time (GMT), but GMT is no longer precisely defined by the scientific community . </P> <P> The first Coordinated Universal Time was informally adopted on 1 January 1960, but the official abbreviation of UTC and the official English name of Coordinated Universal Time (along with the French equivalent), was not adopted until 1967 . </P>

The universal time coordinate is also known as