ecliptic

[ ih-klip-tik ]

noun

1. Astronomy.
   1. the great circle formed by the intersection of the plane of the earth's orbit with the celestial sphere; the apparent annual path of the sun in the heavens.
   2. an analogous great circle on a terrestrial globe.
2. Astrology. the great circle of the ecliptic, along which are located the 12 houses and signs of the zodiac.

adjective

1. pertaining to an eclipse.
2. pertaining to the ecliptic.

ecliptic

/ ɪˈklɪptɪk /

noun

1. astronomy
   1. the great circle on the celestial sphere representing the apparent annual path of the sun relative to the stars. It is inclined at 23.45° to the celestial equator. The poles of the ecliptic lie on the celestial sphere due north and south of the plane of the ecliptic
   2. ( as modifier )

      the ecliptic plane

2. an equivalent great circle, opposite points of which pass through the Tropics of Cancer and Capricorn, on the terrestrial globe

adjective

1. of or relating to an eclipse

ecliptic

/ ĭ-klĭp′tĭk /

1. The great circle on the celestial sphere that represents the Sun's apparent path among the background stars in one year. The northernmost point this path reaches on the celestial sphere is the Tropic of Cancer, its southernmost point is the Tropic of Capricorn, and it crosses the celestial equator at the points of vernal and autumnal equinox.
2. ◆ The plane of the ecliptic is the imaginary plane that intersects the celestial sphere along the ecliptic, and the north and south ecliptic poles are the points where a perpendicular line through the middle of this plane intersect the sphere. The plane of the ecliptic corresponds to the plane in which the Earth orbits the Sun. If the Earth's axis were not tilted, the ecliptic would be identical to the celestial equator and the ecliptic poles identical to the celestial poles. In this case, the Sun's path would not move northward or southward from the equator during the year. As it is, the plane of the celestial equator is tilted 23.45° to the plane of the ecliptic, corresponding to the tilt of the Earth's axis with respect to its orbital plane, giving the Sun its apparent northward and southward movement among the background stars.
3. See illustration at celestial sphere

Derived Forms

• eˈcliptically, adverb

Other Words From

• e·clipti·cal·ly adverb
• none·cliptic adjective
• none·clipti·cal adjective
• none·clipti·cal·ly adverb
• une·cliptic adjective
• une·clipti·cal adjective
• une·clipti·cal·ly adverb

Word History and Origins

Origin of ecliptic¹

1350–1400; Middle English < Medieval Latin eclīptica, feminine of eclīpticus < Greek ekleiptikós, equivalent to ekleíp ( ein ) ( eclipse ) + -tikos -tic

Example Sentences

Conjunctions occur frequently in our solar system because "the planets orbit around the Sun in approximately the same plane - the ecliptic plane - and thus trace similar paths across our sky", according to Nasa.

From BBC

Because we’re in that plane, we see it edge on as a line across the sky called the ecliptic.

From Scientific American

That trajectory eventually took Voyager 1 “north” and out of the ecliptic—the plane of the solar system.

From Scientific American

Babylonian astronomers had previously measured the positions of some stars around the zodiac, the constellations that lie along the ecliptic—the Sun’s annual path against the fixed stars, as seen from Earth.

From Scientific American

Space physicists later worked out that models had largely ignored interstellar magnetic fields, which compress the heliosphere below the ecliptic, Provornikova says.

From Science Magazine

Related Words

• ring
• sphere