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

  • noun The plane defined by the earth's orbit projected onto the celestial sphere, along which the sun appears to move as viewed from the earth.
  • noun A great circle inscribed on a terrestrial globe inclined at an approximate angle of 23°27′ to the equator and representing the apparent motion of the sun in relation to the earth during a year.
  • noun The plane defined by the earth's solar orbit, with the sun at its center, that extends throughout the solar system.

from The Century Dictionary.

  • Pertaining to an eclipse.
  • Pertaining to the apparent path of the sun in the heavens: as, ecliptic constellations.
  • noun In astronomy, a great circle of the heavens in the plane of the earth's orbit, or that of the apparent annual motion of the sun among the stars.
  • noun A great circle drawn upon a terrestrial globe, tangent to the tropics.

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

  • noun (Astron.) A great circle of the celestial sphere, making an angle with the equinoctial of about 23° 28'. It is the apparent path of the sun, or the real path of the earth as seen from the sun.
  • noun (Geog.) A great circle drawn on a terrestrial globe, making an angle of 23° 28' with the equator; -- used for illustrating and solving astronomical problems.
  • adjective Pertaining to the ecliptic.
  • adjective Pertaining to an eclipse or to eclipses.
  • adjective (Astron.) the space of 12° on the moon's orbit from the node, within which, if the moon happens to be at full, it will be eclipsed.
  • adjective the space of 17° from the lunar node, within which, if a conjunction of the sun and moon occur, the sun will be eclipsed.

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

  • noun astronomy The apparent path of the Sun in the sky. More accurately, it is the intersection of the celestial sphere with the plane of the ecliptic, which is the geometric plane containing the mean orbit of the Earth around the Sun. So named because an eclipse can occur only when the Moon lies on this plane.

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

  • noun the great circle representing the apparent annual path of the sun; the plane of the Earth's orbit around the sun; makes an angle of about 23 degrees with the equator


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

[Middle English ecliptik, from Medieval Latin (līnea) eclīptica, ecliptic (line), from Latin eclīpticus, of an eclipse, from Greek ekleiptikos, from ekleipein, to fail to appear; see eclipse.]


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  • Now those noble golden coins of South America are as medals of the sun and tropic token-pieces. Here palms, alpacas, and volcanoes; sun's disks and stars, ecliptics, horns-of-plenty, and rich banners waving, are in luxuriant profusion stamped ...

    - Melville, Moby-Dick, ch. 99

    July 29, 2008

  • Another usage on colures.

    October 12, 2008