universal time

noun
(often initial capital letters) Greenwich Time, Abbreviation: UT

Origin:
1885–90

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World English Dictionary
universal time
 
n
1.  UT (from 1928) name adopted internationally for Greenwich Mean Time (measured from Greenwich midnight), now split into several slightly different scales, one of which (UT1) is used by astronomers
2.  Also called: universal coordinated time, UTC An internationally agreed system for civil timekeeping introduced in 1960 and redefined in 1972 as an atomic timescale. Available from broadcast signals, it has a second equal to the International Atomic Time (TAI) second, the difference between UTC and TAI being an integral number of seconds with leap seconds inserted when necessary to keep it within 0.9 seconds of UT1

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Dictionary.com's 21st Century Lexicon
Main Entry:  universal time
Part of Speech:  n
Definition:  See military time
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American Heritage
Science Dictionary
universal time  
The mean time for the meridian at Greenwich, England (0° longitude), which runs through the former site of the Royal Observatory. It is based on the sidereal period of Earth's rotation and is used as a basis for calculating standard clock time throughout most of the world. Also called Greenwich Mean Time. Compare coordinated universal time.
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American Heritage
Cultural Dictionary

universal time definition


The measure of time obtained from the rotation of the Earth, also known as Greenwich mean time, after the Greenwich Observatory in England. The world's time standard today is Coordinated Universal Time, which is kept by atomic clocks. The two universal times are kept in synchronization by the occasional insertion of leap seconds into the year.

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FOLDOC
Computing Dictionary

Universal Time definition

time, standard
(UT) The mean solar time along the prime meridian (0 longitude) that runs through the Greenwich Observatory outside of London, UK, where the current system originated. UT is tied to the rotation of the Earth in respect to the fictitious "mean Sun".
Greenwich Mean Time (GMT) was measured from Greenwich mean midday until 1925 when the reference point was changed from noon to midnight and the name changed to "Universal Time".
There are three separate definitions, UT0, UT1, and UT2, depending on which corrections have been applied to the Earth's motion. Coordinated Universal Time is kept within 0.9 seconds of UT1, by addition of leap seconds to International Atomic Time.
(2001-08-02)

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Example sentences
From the perspective of relativity, a universal time is an illusion-but an illusion our society needs to function.
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