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n. Abbr. UT
The time at the Prime Meridian, calculated from the apparent rotation of the celestial sphere and used primarily by astronomers.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
1. (Units) (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. Abbreviation: UT
2. (Units) Also called: universal coordinated time 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. Abbreviation: UTC
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
The mean time for the meridian at Greenwich, England (0° longitude), which runs through the former site of the Royal Observatory. It is used as a basis for calculating time throughout most of the world. Also called Greenwich Mean Time.
The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
A measure of time that conforms, within a close approximation, to the mean diurnal rotation of the Earth and serves as the basis of civil timekeeping. Universal Time (UT1) is determined from observations of the stars, radio sources, and also from ranging observations of the moon and artificial Earth satellites. The scale determined directly from such observations is designated Universal Time Observed (UTO); it is slightly dependent on the place of observation. When UTO is corrected for the shift in longitude of the observing station caused by polar motion, the time scale UT1 is obtained. When an accuracy better than one second is not required, Universal Time can be used to mean Coordinated Universal Time. Also called ZULU time. Formerly called Greenwich Mean Time.
Dictionary of Military and Associated Terms. US Department of Defense 2005.
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|Noun||1.||universal time - the local time at the 0 meridian passing through Greenwich, England; it is the same everywhere|
time - the continuum of experience in which events pass from the future through the present to the past
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