Ecliptic
The path apparently described by the sun in his annual course
through the heavens. Eclipses happen only when the moon is in or near
the same plane.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894 More on Ecliptic from Fact Monster:
 ecliptic  ecliptic ecliptic , the great circle on the celestial sphere that lies in the plane of the ...
 ecliptic coordinate system  ecliptic coordinate system ecliptic coordinate system, an astronomical coordinate system in which ...
 obliquity of the ecliptic  obliquity of the ecliptic: obliquity of the ecliptic: see inclination.
 inclination  inclination inclination, in astronomy, the angle of intersection between two planes, one of which ...
 node  node node, in astronomy, point at which the orbit of a body crosses a reference plane. One ...
