Definitions

from The American Heritage® Dictionary of the English Language, 5th Edition.

  • adjective Relating to an equinox.
  • adjective Relating to the celestial equator.
  • noun A violent storm of wind and rain occurring at or near the time of the equinox.

from The Century Dictionary.

  • Pertaining to the equinoxes; marking an equal length of day and night: as, the equinoctial line, or equator.
  • Pertaining to the regions or climate of the equinoctial line, or equator; in or near that line: as, equinoctial heat; an equinoctial sun; equinoctial wind.
  • Occurring at the time of an equinox: as, an equinoctial storm.
  • noun In astronomy, the celestial equator: so called because when the sun is on it the days and nights are of equal length in all parts of the world.
  • noun A gale or storm occurring at or near the time of an equinox.

from the GNU version of the Collaborative International Dictionary of English.

  • noun The equinoctial line.
  • adjective Pertaining to an equinox, or the equinoxes, or to the time of equal day and night.
  • adjective Pertaining to the regions or climate of the equinoctial line or equator; in or near that line
  • adjective Pertaining to the time when the sun enters the equinoctial points.
  • adjective (Astron.) the meridian passing through the equinoctial points.
  • adjective (Astron.) the celestial equator; -- so called because when the sun is on it, the nights and days are of equal length in all parts of the world. See Equator.
  • adjective (Astron.) the two points where the celestial and ecliptic intersect each other; the one being in the first point of Aries, the other in the first point of Libra.
  • adjective (Astron.) reckoned in any year from the instant when the mean sun is at the mean vernal equinoctial point.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • adjective Of or relating to an equinox.
  • adjective astronomy Of or relating to a celestial or terrestrial equator.
  • noun The great circle midway between the celestial poles; the celestial equator.
  • noun rare The terrestrial equator.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adjective relating to the vicinity of the equator
  • noun the great circle on the celestial sphere midway between the celestial poles
  • adjective relating to an equinox (when the lengths of night and day are equal)

Etymologies

from The American Heritage® Dictionary of the English Language, 4th Edition

[Middle English equinoxial, from Old French, from Latin aequinoctiālis, from aequinoctium, equinox; see equinox.]

Examples

  • The equator is the line C, D, which upon the globe is a circle, and is sometimes called the equinoctial: Upon this circle the degrees of longitude are reckoned, beginning at C, and counting all round the globe till you come to C again; and O is the middle of the world between A and B, which are the two poles thereof: A representing the

    A Museum for Young Gentlemen and Ladies Or, a Private Tutor for Little Masters and Misses

  • As one half of the ecliptic is north, and the other half south, of the equator, the line of intersection of their planes is at two points which are known as the equinoctial points, because, when the Sun on his upward and downward journey arrives at either of them the days and nights are of equal length all over the world.

    The Astronomy of Milton's 'Paradise Lost'

  • The two first stars named are exactly on what is called the equinoctial line.

    The Wonder Island Boys: The Tribesmen

  • If we suppose the south pole to be the centre of a chart of which the equinoctial is the circumference, we shall then discern four quarters, of the contents of which, if we could give a full account, this part of the world would be perfectly discovered.

    Early Australian Voyages: Pelsart, Tasman, Dampier

  • During colonial times, the proximity of many of these storms to the autumnal equinox led early Americans to call them "equinoctial" storms or "line" storms, thought to be a reference to the tropic of cancer, the imaginary "line" near the hurricane breeding zone that encircles the world at approximately 23 ½ degrees N. latitude (it slowly changes position over time).

    Otto may form, but tropical season slowing?

  • This was the beginning of a long and dreary autumnal storm, a deferred "equinoctial," as many considered it.

    The Atlantic Monthly, Volume 07, No. 42, April, 1861

  • This discouraging condition of affairs sorely afflicted her, and produced a kind of equinoctial agitation in the Hollis kitchen.

    Sandy

  • This was probably the "equinoctial," and when it was over there would be a delightful Indian summer, and the turnips would grow nicely.

    Rudder Grange

  • This was the beginning of a long and dreary autumnal storm, a deferred "equinoctial," as many considered it.

    Complete Project Gutenberg Oliver Wendell Holmes, Sr. Works

  • This was the beginning of a long and dreary autumnal storm, a deferred "equinoctial," as many considered it.

    Elsie Venner

Comments

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  • "'...must have been thinking of the summer, not the season of equinoctial gales or the even more dreadful turning winter storms.'"

    —P. O'Brian, The Yellow Admiral, 112

    March 19, 2008

  • Another usage on colures.

    October 12, 2008

  • from Thoreau's A Week on the Concord and Merrimack Rivers

    July 19, 2009