Middle English ecliptik, from Late Latin ecliptica linea, literally, line of eclipses
First Known Use: 14th century
Definition of ECLIPTIC
: the great circle of the celestial sphere that is the apparent path of the sun among the stars or of the earth as seen from the sun : the plane of the earth's orbit extended to meet the celestial sphere
Great circle that is the apparent path of the Sun among the constellations in the course of a year; from another viewpoint, the projection on the celestial sphere of the orbit of Earth around the Sun, which intersects the plane of the celestial equator at the vernal and autumnal equinoxes. The constellations of the zodiac are arranged along the ecliptic.