How do you spell Zodiac

Available Definitions:
1)  n. - An imaginary belt in the heavens, 16¡ or 18¡ broad, in the middle of which is the ecliptic, or sun's path. It comprises the twelve constellations, which one constituted, and from which were named, the twelve signs of the zodiac.
2)  n. - A figure representing the signs, symbols, and constellations of the zodiac.
3)  n. - A girdle; a belt.