greenwich mean time

Greenwich Time

noun
the time as measured on the prime meridian running through Greenwich, England: used in England and as a standard of calculation elsewhere.
Also called Greenwich Mean Time, Greenwich Civil Time, universal time, Universal Time.


Origin:
1840–50

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Collins
World English Dictionary
Greenwich Mean Time or Greenwich Time
 
n
See universal time 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midnight: formerly a standard time in Britain and a basis for calculating times throughout most of the world, it has been replaced by an atomic timescale
 
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
 
Greenwich Time or Greenwich Time
 
n
 
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

Collins English Dictionary - Complete & Unabridged 10th Edition
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American Heritage
Science Dictionary
Greenwich mean Time   (grěn'ĭch)  Pronunciation Key 
See universal time.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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FOLDOC
Computing Dictionary

Greenwich Mean Time definition

time, standard
(GMT) The local time on the Greenwich meridian, based on the hypothetical mean sun (which averages out the effects of the Earth's elliptical orbit and its tilted axis). GMT is the basis of the civil time for the UK.
In 1925 the reference point was changed from noon to midnight and it was recommended that the term "Universal Time" should be used for the new GMT.
Authorities disagreed on whether GMT equates with UT0 or UT1, however the differences between the two are of the order of thousandths of a second. GMT is no longer used for scientific purposes.
(2001-08-02)
The Free On-line Dictionary of Computing, © Denis Howe 2010 http://foldoc.org
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