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ui
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Plural
equinoxes
1
(astronomy) either of the two celestial points at which the celestial equator intersects the ecliptic
Synonyms:
2
either of the two moments in a year when the Sun, in its apparent motion along the ecliptic, crosses the celestial equator, resulting in approximately equal periods of daylight and darkness worldwide
- The spring equinox marks the beginning of spring in the Northern Hemisphere.
- During the autumn equinox, the length of day and night are nearly equal.
- The equinox occurs twice a year, once in March and once in September.
- On the equinox, the Sun rises due east and sets due west.
- The equinoxes are important for astronomers studying the Earth's tilt and orbit.