1 a a belt of the heavens limited by lines about 8° from the ecliptic on each side, including all apparent positions of the sun, moon, and planets as known to ancient astronomers, and divided into twelve equal parts (signs of the zodiac), each formerly containing the similarly named constellation but now by precession of the equinoxes coinciding with the constellation that bears the name of the preceding sign: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn(us), Aquarius, Pisces. b a diagram of these signs.
2 a complete cycle, circuit, or compass.
Etymology: ME f. OF zodiaque f. L zodiacus f. Gk zoidiakos f. zoidion sculptured animal-figure, dimin. of zoion animal
Useful english dictionary. 2012.