Greenwich Mean Time

British  

noun

1.  GMT.  mean solar time on the 0° meridian passing through Greenwich, England, measured from midnight: formerly a standard time in Britain and a basis for calculating times throughout most of the world, it has been replaced by an atomic timescale See universal time

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Greenwich Mean Time Scientific  

/ grĕn′ĭch /

1. See universal time

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Usage

The name Greenwich mean time is ambiguous, having been measured from mean midday in astronomy up to 1925, and is not used for scientific purposes. It is generally and incorrectly used in the sense of universal coordinated time , an atomic timescale available since 1972 from broadcast signals, in addition to the earliest sense of universal time , adopted internationally in 1928 as the name for GMT measured from midnight