equinox
noun
ˈe-
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Equinox and the Seasons
Equinox descends from aequus, the Latin word for "equal" or "even," 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
Alexis Simmerman, Austin American Statesman, 5 Apr. 2026
Well, the vernal equinox, or start of spring, is fixed as March 21.
—Manon Bischoff, Scientific American, 4 Apr. 2026
Under the bill, flags would be required to fly at half-staff on the first Friday and Saturday after the full moon that occurs on or after the spring equinox each year.
—Sam Stevenson, MSNBC Newsweek, 1 Apr. 2026
Others speculate that it was inspired by the vernal equinox, or the first day of spring in the Northern Hemisphere, when Mother Nature fooled people with changing, unpredictable weather.
—Rick Kogan, Chicago Tribune, 31 Mar. 2026
See All Example Sentences for equinox
Cite this Entry
“Equinox.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/equinox. Accessed 6 Apr. 2026.
Copy CitationKids Definition
equinox
noun
ˈek-wə-
Latin equinoxium (same meaning), derived from earlier Latin aequi- "equal" and noct-, nox "night" — related to nocturnal
