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Greenwich mean time

Greenwich mean time or Greenwich meridian time (GMT), the former name for mean solar time at the original site of the Royal Observatory in Greenwich, England, which is located on the prime meridian. In 1925 the numbering system was changed to make GMT equivalent to civil time at the prime meridian, and in 1928 the International Astronomical Union changed the designation of the standard time of the prime meridian to universal time (UT), which is now in general use.

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Greenwich Mean Time

Greenwich Mean Time (GMT) Local time at Greenwich, London, situated on the prime meridian (0° longitude) that passes through the Old Royal Observatory. It has been used as the basis for calculating standard time in various parts of the world since 1884.

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Greenwich Mean Time

Green·wich Mean Time (abbr.: GMT) (also Green·wich time) the mean solar time at the Greenwich meridian, adopted as the standard time in a zone that includes the British Isles.

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GMT

GMT • abbr. Greenwich Mean Time.

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GMT

GMT Abbreviation of Greenwich Mean Time

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GMT

GMT Greenwich Mean Time

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