autumnal equinox

American  

[aw-tuhm-nl ee-kwuh-noks, ek-wuh-noks] / ɔˈtʌm nl ˈi kwəˌnɒks, ˈɛk wəˌnɒks /

noun

1. equinox1

2. Also called autumnal point.  the position of the sun at the time of the autumnal equinox.

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autumnal equinox British  

noun

1. the time at which the sun crosses the plane of the equator away from the relevant hemisphere, making day and night of equal length. It occurs about Sept 23 in the N hemisphere (March 21 in the S hemisphere)

2. astronomy

   1. the point, lying in the constellation Virgo, at which the sun's ecliptic intersects the celestial equator

   2. the time at which this occurs as the sun travels north to south (23 September)

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autumnal equinox Scientific  

/ ô-tŭm′nəl /

1. See under equinox

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Etymology

Origin of autumnal equinox

First recorded in 1670–80

Example Sentences

See Examples For:

autumnal equinox

Or, as we say north of the equator, happy autumnal equinox!

From Scientific American ● Sep. 22, 2023

On September 23, 2023, the autumnal equinox will signal the coming of fall for the Northern Hemisphere.

From National Geographic ● Sep. 21, 2023

This year, the warm days have not only surpassed the September 22 autumnal equinox but are expected to continue through Oct.

From Seattle Times ● Oct. 2, 2022

Pull your sweaters from storage, and get your yard rakes ready: The autumnal equinox — the official astronomical start to fall — occurs Sept. 22 at 9:04 p.m.

From Washington Post ● Aug. 26, 2022

At the autumnal equinox of 1794 Pitt was confronted by a far more serious crisis than at the beginning of the war in February 1793.

From William Pitt and the Great War by Rose, John Holland