si·​de·​re·​al | \ sī-ˈdir-ē-əl How to pronounce sidereal (audio) , sə- \

Definition of sidereal

: of, relating to, or expressed in relation to stars or constellations : astral

Examples of sidereal in a Sentence

Recent Examples on the Web Called sidereal time, the measurement calculates the length of a day by comparing the earth's rotation to the stars. Aaron Pressman, Fortune, "Data Sheet—Amazon Makes Overdue Price Cuts at Whole Foods," 12 Apr. 2017 One tweet, in particular, has birthed a fair number of inky astronauts floating across a sidereal arm. Jesse Lichtenstein, New York Times, "A Whimsical Wordsmith Charts a Course Beyond Twitter," 15 June 2017 With this definition, a sidereal year is something like 365.256363 solar days. Rhett Allain, WIRED, "Why Is There a Leap Year?," 29 Feb. 2012

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sidereal.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of sidereal

1612, in the meaning defined above

History and Etymology for sidereal

Latin sidereus, from sider-, sidus star, constellation

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Time Traveler for sidereal

Time Traveler

The first known use of sidereal was in 1612

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Cite this Entry

“Sidereal.” Dictionary, Merriam-Webster, Accessed 27 Sep. 2020.

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