sidereal day

American  

noun

Astronomy.

1. the interval between two successive passages of the vernal equinox over the meridian, being about four minutes shorter than a mean solar day.

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sidereal day British  

noun

1. See day

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Etymology

Origin of sidereal day

First recorded in 1785–95

Compare meaning

How does sidereal-day compare to similar and commonly confused words? Explore the most common comparisons:

• sidereal day vs. solar day

Example Sentences

So the solar day is about 4 minutes longer than the sidereal day.

From Textbooks • Oct. 13, 2016

However, astronomers also use a sidereal day, which is defined in terms of the rotation period of Earth with respect to the stars.

From Textbooks • Oct. 13, 2016

In a part of Earth’s orbit where Earth is moving faster than usual around the Sun, would the length of the sidereal day change?

From Textbooks • Oct. 13, 2016

Up to the mid-20th century, the sidereal day, the period of the earth’s rotation on its axis in relation to the stars, was used to determine standard time.

From Scientific American • Dec. 31, 2011

The mean solar days are all exactly the same length; they are equal to the length of the average apparent solar day; and they are each four minutes longer than a sidereal day.

From The Astronomy of the Bible An Elementary Commentary on the Astronomical References of Holy Scripture by Maunder, E. Walter (Edward Walter)