The zodiac is a belt in space that extends approximately 9° above and below the ecliptic. The ecliptic is an imaginary plane in space that contains the Sun and most planets of our solar system. From Earth, the ecliptic appears to be a line through the sky along which planets move. For example, if you go out into the night sky and observe the Moon and several planets, you will notice that you can draw a straight line through all of them. This line is the ecliptic, and the area immediately around the ecliptic is the zodiac.
Along the zodiac there are twelve constellations known as the zodiac constellations. These constellations are used in astrology, which assigns a star sign to each person by determining which constellation the Sun is passing through at the time of their birth.