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.

---

sidereal day British  

noun

1. See day

---

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

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

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

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

Then a sidereal day is three minutes fifty-six seconds shorter, than a solar day of twenty-four hours.

From Conversations on Natural Philosophy, in which the Elements of that Science are Familiarly Explained by Jones, Thomas P.