equinox

noun
equi·​nox | \ ˈē-kwə-ˌnäks How to pronounce equinox (audio) , ˈe- How to pronounce equinox (audio) \

Definition of equinox

1 : either of the two points on the celestial sphere where the celestial equator intersects the ecliptic
2 : either of the two times each year (as about March 21 and September 23) when the sun crosses the equator and day and night are everywhere on earth of approximately equal length

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Equinox and the Seasons

Equinox descends from aequus, the Latin word for "equal," and nox, the Latin word for "night"—a fitting history for a word that describes days of the year when the daytime and nighttime are equal in length. In the northern hemisphere, the vernal equinox marks the first day of spring and occurs when the sun moves north across the equator. (Vernal comes from the Latin word ver, meaning "spring.") The autumnal equinox marks the first day of autumn in the northern hemisphere and occurs when the sun crosses the equator going south. In contrast, a solstice is either of the two moments in the year when the sun's apparent path is farthest north or south from the equator.

Examples of equinox in a Sentence

Recent Examples on the Web

But one strong possibility is that it was used to mark solstices and equinoxes. Brian Resnick, Vox, "The winter solstice is Friday: 8 things to know about the shortest day of the year," 18 Dec. 2018 Endurance training: Equinox over the decades September 23, 1991 The first Equinox opens, on the autumnal equinox, on Manhattan’s Upper West Side. Howie Kahn, WSJ, "The Hotel Where You’ll Be ‘Sleep-Coached’ Into Bed," 27 Mar. 2019 The date of Easter varies — it's determined by the moon and usually falls on the first Sunday after the first full moon on or after the Spring equinox. Woman's Day Staff, Woman's Day, "When Is Palm Sunday? Here's Everything You Need to Know," 4 Mar. 2019 Meteorological spring starts today with astronomical spring arriving with the vernal equinox the morning of March 20. Joe Songer, AL.com, "Spring arrives early as warmer temperatures have flowers blooming and wildlife more active," 7 Jan. 2018 October 31 through November 1 is also Samhain, halfway between the autumn equinox and the winter solstice, and a holiday marking the end of the harvest season and the start of winter believed to be of Celtic pagan origin. Sophie Saint Thomas, Allure, "Make Beauty Is Having a Big Sale on Its Makeup and Skin Care to Celebrate the Full Moon," 25 Oct. 2018 There are ties to Druidic and pagan culture, and the groups still gather there annually to celebrate equinoxes and solstices. Bridget Hallinan, Condé Nast Traveler, "15 Beautiful Sacred Sites Around the World," 29 Mar. 2018 Below, see a beautiful composite image of Saturn on its equinox captured by the Cassini spacecraft (RIP) in 2009. Brian Resnick, Vox, "The winter solstice is Friday: 8 things to know about the shortest day of the year," 18 Dec. 2018 Easter occurs on the first Sunday after the Paschal full moon, which is the first full moon on or after the spring equinox, according to BBC. Woman's Day Staff, Woman's Day, "When Is Lent? Here's Everything You Need to Know," 11 Jan. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'equinox.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of equinox

14th century, in the meaning defined at sense 1

History and Etymology for equinox

Middle English, from Anglo-French or Medieval Latin; Anglo-French equinocce, from Medieval Latin equinoxium, alteration of Latin aequinoctium, from aequi- equi- + noct-, nox night — more at night

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Last Updated

16 Apr 2019

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Time Traveler for equinox

The first known use of equinox was in the 14th century

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More Definitions for equinox

equinox

noun

English Language Learners Definition of equinox

: a day when day and night are the same length

equinox

noun
equi·​nox | \ ˈē-kwə-ˌnäks How to pronounce equinox (audio) , ˈe-kwə-\

Kids Definition of equinox

: either of the two times each year (as in spring around March 21 and in fall around September 23) when the sun's center crosses the equator and day and night are everywhere of equal length

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More from Merriam-Webster on equinox

Rhyming Dictionary: Words that rhyme with equinox

Spanish Central: Translation of equinox

Nglish: Translation of equinox for Spanish Speakers

Britannica English: Translation of equinox for Arabic Speakers

Britannica.com: Encyclopedia article about equinox

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