ecliptic

The apparent path of the sun across the sky over the course of a year — the plane of Earth's orbit projected onto the celestial sphere. The ecliptic is the line along which eclipses occur (the Moon must cross it to block the sun), the road the planets travel (all orbiting in roughly the same plane), and the belt through which the zodiac constellations are strung. It is the solar system's equator, drawn on the sky.