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
Carlie Procell, USA Today, 16 Apr. 2025
Now, a couple of weeks after the autumnal equinox in the southern hemisphere, the Sun has set on the South Pole until September.
—ArsTechnica, 1 Apr. 2025
The result is that auroras are twice as likely around the equinoxes in late March and late September.
—Jamie Carter, Forbes, 25 Mar. 2025
The vernal equinox, the astronomical event that occurs when the sun aligns with the Earth's equator, will begin at 5:01 a.m. EDT on Thursday.
—Greta Cross, USA TODAY, 20 Mar. 2025
See All Example Sentences for equinox
Cite this Entry
“Equinox.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/equinox. Accessed 3 May. 2025.
Copy CitationKids Definition
equinox
noun
ˈek-wə-
Latin equinoxium (same meaning), derived from earlier Latin aequi- "equal" and noct-, nox "night" — related to nocturnal
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