Ecliptic (noun)

1. The great circle on the celestial sphere that is the apparent path of the sun against the background of stars.
2. The plane of the earth's orbit around the sun.

Origin:

Late 16th century: from latin eclipticus, from greek ekleiptikos, from ekleipein 'to leave out, fail', because the sun appears to 'fail' at certain times in this plane.

Examples:

1. The ecliptic intersects with the celestial equator at two points, known as the equinoxes.
2. The planets of our solar system all lie close to the ecliptic.
3. The ecliptic provides a useful reference for mapping the positions of celestial objects.
4. The tilt of the earth's axis relative to the ecliptic affects the changing of the seasons.
5. The ecliptic was an important concept in ancient astronomy, used to predict eclipses and other celestial events.