equinox
nounUK /ˈɛkwɪnɒks/ · US /ˈɛkwəˌnɑks/
Etymology
PIE word *nókʷts From Middle English equinox, equinoxe, equynox (“one of the two periods in the year when the day and night are of equal length, equinox; either the zodiac sign Aries or Libra, in which the sun crosses the celestial equator”), from Old French equinoce, equinoxe (modern French équinoxe), or from its etymon Medieval Latin ēquinoxium, ēquinoctium, from Latin aequinoctium (“equinox”), from aequus (“equal”) + nox (“night”) (ultimately derived from Proto-Indo-European *nókʷts (“night”)) + -ium (suffix forming abstract nouns). The Latin word, ultimately adopted in Middle English and modern English, displaced Old English efnniht (modern English evennight). The rare alternative plural form equinoctes treats equinox as if it were a Latin word; the plural of Latin nox (“night”) is noctēs.
One of two times in the year (one in March and the other in September) when the length of the day and the night are equal, which occurs when the sun is directly overhead at the equator; this marks the beginning of spring in one hemisphere and autumn in the other.
- [T]he Months of March and September, the tvvo Æquinoxes of Our year, are the moſt vvindy and tempeſtuous, the moſt unſettled and unequable of Seaſons in moſt Countries of the VVorld.1692 December 15, Richard Bentley, A Confutation of Atheism from the Origin and Frame of the World. The Third and Last Part. […], London: […] H[enry] Mortlock […], published 1693, →OCLC, pages 25–26:
- The four grand and ſolemn Bardic days are, of ancient uſage, the tvvo equinoxes, and the tvvo ſolſtices; the nevv and full moons are alſo, ſubordinately, ſolemn Bardic days: […]1793 September 22, Edward Williams, “Ode on Converting a Sword into a Pruning Hook”, in Poems, Lyric and Pastoral. […], London: […] J[ohn] Nichols; […], published 1794, →OCLC, footnote *, pages 160–161:
4 more examples
- [H]e [Milton] believed, his poetic vein only flowed from the autumnal to the vernal equinox; and, in his essay on Education, he doubts whether, in the fine days of spring, any study can be accomplished by young men.(Can we date this quote?), Ralph Waldo Emerson, “Milton”, in The Natural History of the Intellect (Emerson’s Complete Works; XII), Riverside edition, London: The Waverley Book Company, published 1893, →OCLC, page 155:
- Live long, nor feel in head or chest / Our changeful equinoxes, / Till mellow Death, like some late guest, / Shall call thee from the boxes.1842, Alfred Tennyson, “Will Waterproof’s Lyrical Monologue”, in Poems. […], volume II, London: Edward Moxon, […], →OCLC, page 194:
- 21. Report the experiments, if conveniently they may, at both the solstices and equinoctes. / 22. Observe accurately the time of the sun’s rising on the top of the hill and below, and note the difference.1848, Charles Richard Weld, chapter V, in A History of the Royal Society, with Memoirs of the Presidents. […], volume I, London: John W[illiam] Parker, […], →OCLC, page 100:
- For [Julius] Cæsar says, that on the night of the fourth day after his landing there was a full moon. He had before mentioned that the summer was far spent, and the æquinox not come, hence, the full moon must have been either in July or August.1854, John Williams, “Pro-consul. b.c. 55.”, in The Life of Julius Cæsar, London; New York, N.Y.: G[eorge] Routledge & Co., […], →OCLC, page 195:
Also, Figuratively The circumstance of a twenty-four hour time period having the day and night of equal length.
- [D]oe but ſee his vice, / Tis to his vertue, a iuſt equinox, / The one as long as th'other: […]c. 1603–1604 (date written), William Shakespeare, The Tragœdy of Othello, the Moore of Venice. […] (First Quarto), London: […] N[icholas] O[kes] for Thomas Walkley, […], published 1622, →OCLC, [Act II, scene iii], page 32:
Astronomy, Natural sciences One of the two points in space where the apparent path of the Sun intersects with the equatorial plane of the Earth.
Obsolete, Rare A gale (“very strong wind”) once thought to occur more frequently around the time of an equinox (sense 1), now known to be a misconception; an equinoctial gale.
- The paſſage yet vvas good, the vvind, 'tis true, / VVas ſomevvhat high, but that vvas nothing nevv, / Nor more than uſual Equinoxes blevv.1687, [John Dryden], “The Third Part”, in The Hind and the Panther. A Poem, in Three Parts, 2nd edition, London: […] Jacob Tonson […], →OCLC, page 101:
- The Equinox drove the sand into their faces or round their legs, as they dived among the sheep-haunted hollows.1920 September 1, Rudyard Kipling, “The Satisfaction of a Gentleman”, in The London Magazine, London: Hunt and Clarke, […], →OCLC; republished on the website of The Kipling Society, accessed 7 September 2022, archived from the original on 22 Dec 2021:
Astronomy, Natural sciences Obsolete A celestial equator (“great circle on the celestial sphere, coincident with the plane of the Earth's equator (the equatorial plane)”); also, the Earth's equator.
- [T]hey [seals] are over all the American Coaſt of the South Seas, from Terra del Fuego, up to the Equinoctial Line: but to the North of the Equinox again, in theſe Sea, I never ſavv any, till as far as 21 North Lat[itude].1697, William Dampier, chapter IV, in A New Voyage Round the World. […], London: […] James Knapton, […], →OCLC, page 90:
- Derived terms
- equinox flower, equinoxial, precession of the equinoxes
- Related terms
- equinoctal, equinoctial, equinoctially, equinoctium, interequinoctial, equilux
- Hyponyms
- autumnal equinox, autumn equinox, fall equinox, northward equinox, southward equinox, spring equinox, vernal equinox
- Coordinate terms
- solstice