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
From the M-W Editors
equinox was our Word of the Day on 09/23/2015. Hear the podcast!
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Recent Examples of equinox from the Web
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A summer of music in San Clemente is already in full-blast mode, even as the summer equinox is yet to arrive on Tuesday, June 20.
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On May 3, the researchers experienced their last sunrise and will work through Antarctica's dark winter until the September equinox, the agency said.
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The seasons are marked by two solstices and two equinoxes.
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And, sure enough, by the time of spring equinox, March 20, most of the country was in full-blown spring.
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In March, some friends of mine, retirees who are amateur singers and musicians, were hired as extras for a ceremony on the spring equinox.
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With the equinox of spring last month, so began the season of seeds sprouting, weather changing and enjoying more activities outdoors.
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This year the vernal equinox fell on March 20 and the first full moon after that was on April 11.
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Iranians and others have decorated eggs on Nowruz, the Iranian New Year on the spring equinox.
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.
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.
Origin and Etymology of 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
EQUINOX Defined for English Language Learners
equinox
playDefinition of equinox for English Language Learners
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: a day when day and night are the same length
EQUINOX Defined for Kids
equinox
playDefinition of equinox for Students
: 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
Learn More about equinox
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See 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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