Definition of sidereal year in US English:

sidereal year


  • The orbital period of the earth around the sun, taking the stars as a reference frame, being 20 minutes longer than the tropical year because of precession.

    • ‘Incommensurability between Earth's tropical and sidereal years is easy to understand, yet has confounded more than a few amateur astronomers and astrologers for centuries to millennia.’
    • ‘As we've seen for Mars, Jupiter and Saturn, the sidereal motion of planets is fundamental to determining not only the position of a planet but also its sidereal year around the Sun.’
    • ‘The faster the Earth orbits the Sun, the fewer solar days per sidereal year we see.’
    • ‘The Bikrami solar year actually is not a solar year but a sidereal year.’
    • ‘Because of the precession of the equinoxes the tropical year is shorter by about 21 minutes than the sidereal year (the time taken by the Sun to return to the same place against the background stars).’