Adjacent Words

Equinox definitions

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Webster's 1828 Dictionary

E'QUINOX, n. [L. oequus, equal, and nox, night.]
The precise time when the sun enters one of the equinoctial points, or the first point of Aries, about the 21st of March, and the first point of Libra, about the 23d of September, making the day and the night of equal length. These are called the vernal and autumnal equinoxes. These points are found to be moving backward or westward, at the rate of 50" of a degree in a year. This is called the precession of the equinoxes.

WordNet (r) 3.0 (2005)

n
1: either of two times of the year when the sun crosses the plane of the earth's equator and day and night are of equal length
2: (astronomy) either of the two celestial points at which the celestial equator intersects the ecliptic [syn: equinoctial point, equinox]

Merriam Webster's

noun Etymology: 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 Date: 14th century 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

Britannica Concise

Either of two moments in the year when the sun is exactly above the equator and day and night are of equal length all over the earth. The vernal equinox, when spring begins in the Northern Hemisphere, occurs about March 21, when the sun moves north across the celestial equator. The autumnal equinox falls about September 23, as the sun crosses the celestial equator going south. The term equinox also refers to either of two points in the sky where the ecliptic and the celestial equator (see celestial sphere) intersect. See also solstice.

Oxford Reference Dictionary

n. 1 the time or date (twice each year) at which the sun crosses the celestial equator, when day and night are of equal length. 2 = equinoctial point. Phrases and idioms: autumn (or autumnal) equinox about 22 Sept. spring (or vernal) equinox about 20 March. Etymology: ME f. OF equinoxe or med.L equinoxium for L aequinoctium (as EQUI-, nox noctis night)

Webster's 1913 Dictionary

Equinox E"qui*nox, n. [OE. equinoxium, equenoxium, L. aequinoctium; aequus equal + nox, noctis, night: cf. F. ['e]quinoxe. See Equal, and Night.] 1. The time when the sun enters one of the equinoctial points, that is, about March 21 and September 22. See Autumnal equinox, Vernal equinox, under Autumnal and Vernal. When descends on the Atlantic The gigantic Stormwind of the equinox. --Longfellow. 2. Equinoctial wind or storm. [R.] --Dryden.

Collin's Cobuild Dictionary

(equinoxes) An equinox is one of the two days in the year when day and night are of equal length. In the Chinese calendar, the Spring Equinox always occurs in the second month. N-COUNT: oft supp N

Soule's Dictionary of English Synonyms

n. Equinoctial point, intersection of the equator and the ecliptic.

Moby Thesaurus

aphelion, apogee, astronomical longitude, autumnal equinox, celestial equator, celestial longitude, celestial meridian, circle, colures, ecliptic, equator, equinoctial, equinoctial circle, equinoctial colure, galactic longitude, geocentric longitude, geodetic longitude, great circle, heliocentric longitude, longitude, meridian, orbit, perigee, perihelion, period, small circle, solstice, solstitial colure, summer solstice, trajectory, vernal equinox, winter solstice, zodiac, zone