greenwich mean time

noun

1. the time as measured on the prime meridian running through Greenwich, England: used in England and as a standard of calculation elsewhere.

noun

1. 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midnight: formerly a standard time in Britain and a basis for calculating times throughout most of the world, it has been replaced by an atomic timescaleAbbreviation: GMT See universal time

1. See universal time.