Zodiac.
A belt of twelve constellations through which the Sun's path in the sky - the ecliptic - passes. They are Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Sagittarius, Capricornus, Aquarius and Pisces. Though the ecliptic formerly went only through these twelve constellations, the effects of precession and the precise definitions of constellation boundaries mean that it now also goes through a thirteenth, Ophiuchus.
Since the orbits of all the planets, apart from Pluto, lie very nearly in a plane, the apparent paths of the planets remain in or close to the zodiacal constellations.
In traditional astrological use, the zodiac is divided into twelve equal 30¡ portions, each of which is allocated to a Ôsign', but these do not correspond exactly to the astronomical constellations, which are of varying sizes. The effect of precession has further contributed to increasing disparity between the true position of the Sun and the astrological signs.