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sidereal

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adjective si·de·re·al \sī-ˈdir-ē-əl, sə-\

Definition of sidereal

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



Did You Know?

In Latin, the word for heavenly body is sidus. Latin speakers used that word to form desiderare (from a heavenly body) and considerare (to think about a heavenly body), which were adopted into English as desire and consider. Sidereal, another sidus creation, was first used in English in 1647. Thirty-four years later, an astronomer coined the phrase sidereal year for the time in which the earth completes one revolution in its orbit around the sun, measured with respect to the fixed stars. Not surprisingly, other sidereal measurements of time followed, including the sidereal month, the sidereal day, the sidereal hour, and even the sidereal minute.

Origin of sidereal

Latin sidereus, from sider-, sidus star, constellation


First Known Use: 1647

Other Astronomy Terms


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