zodiac

The zodiac is a celestial coordinate system: a belt in the sky about eight degrees wide that follows the ecliptic, the Sun’s apparent path across the celestial sphere. The belt is divided into twelve equal segments, each associated with a sign: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces. In astronomy, these twelve segments correspond to twelve constellations that lie along or near the ecliptic, known as the zodiacal constellations. The Sun, Moon, and planets travel through this region as observed from Earth, and their positions within the signs are used to describe their apparent motions.

In Western astrology, the zodiac signs are anchored to a tropical scheme: the first sign, Aries, begins at the vernal equinox, and each sign covers 30 degrees of the ecliptic. Because of the precession of the equinoxes, the terrestrial positions of the signs drift relative to the actual constellations, and many Eastern traditions use the sidereal zodiac, which aligns signs with the current positions of the constellations, resulting in different dates for the signs.

Etymology: The term zodiac derives from Greek zōdiakos kýklos, meaning “circle of animals,” a reference to the common animal symbols of the signs. In modern usage, the zodiac is central to astrology, where a person’s sun sign is believed to influence personality and fate, while in astronomy it functions as a mapping framework for the sky along the ecliptic.