Definition
The ecliptic is the great circle on the celestial sphere representing the Sun's apparent annual path. It is the intersection of Earth's orbital plane with the sky. The obliquity ε ≈ 23.44° is the angle between ecliptic and celestial equator.
Zodiac
The zodiac is the band of constellations within about ±8° of the ecliptic. The Sun, Moon and planets stay close to this path because the solar system is nearly flat.
