Definition of ecliptic in English:



  • A great circle on the celestial sphere representing the sun's apparent path during the year, so called because lunar and solar eclipses can only occur when the moon crosses it.

    • ‘An eclipse occurs only if the Moon crosses the ecliptic when very close to either conjunction or opposition, respectively producing solar and lunar eclipses.’
    • ‘The Moon's Nodes are points in space representing the points where the moon's orbit around the earth crosses the ecliptic.’
    • ‘The other planets though also move across the sky on paths close to the ecliptic.’
    • ‘Comets in this group, called the Jupiter family comets, revolve around the Sun near the plane of the ecliptic in the same direction as Earth's orbit.’
    • ‘A lunar eclipse occurs at full moon when the Moon crosses the ecliptic in opposition to the Sun.’


  • Of an eclipse or the ecliptic.

    • ‘The required coincidence of a conjunction with the ecliptic crossing of Venus has some latitude because the solar disc is so much bigger than the image of Venus.’
    • ‘There are also tables which give transformations between different coordinate systems on the celestial sphere, in particular allowing ecliptic coordinates to be transformed into equatorial coordinates.’
    • ‘Second, and more significant, eclipses do not necessarily occur precisely on the node, but rather there is a range of possible positions called the ecliptic limits.’
    • ‘Lunar eclipses occur at the time of a Full Moon, and when the Moon is near one of the nodes of intersection between its orbit and the ecliptic plane.’
    • ‘Another eight years later the node has moved beyond the ecliptic limit, and no transit can take place.’


Late Middle English: via Latin from Greek ekleiptikos, from ekleipein ‘fail to appear’ (see eclipse).