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sidereal day

noun, Astronomy
the interval between two successive passages of the vernal equinox over the meridian, being about four minutes shorter than a mean solar day.
Origin of sidereal day
1785-95 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for sidereal day
  • Beginning of a sidereal day at a given place occurs at the instant the vernal equinox is at upper transit.
British Dictionary definitions for sidereal day

sidereal day

See day (sense 5)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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