sidereal year

noun
plural sidereal years

Definition of sidereal year

: the time in which the earth completes one revolution in its orbit around the sun measured with respect to the fixed stars : 365 days, 6 hours, 9 minutes, and 9.5 seconds of mean time The light-year is defined as the distance light travels in 1 sidereal year— William D. Johnstone

First Known Use of sidereal year

1765, in the meaning defined above

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The first known use of sidereal year was in 1765

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Cite this Entry

“Sidereal year.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/sidereal%20year. Accessed 23 Oct. 2020.

More from Merriam-Webster on sidereal year

Britannica.com: Encyclopedia article about sidereal year

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