- zodiac
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/zoh"dee ak'/, n.1. an imaginary belt of the heavens, extending about 8° on each side of the ecliptic, within which are the apparent paths of the sun, moon, and principal planets. It contains twelve constellations and hence twelve divisions called signs of the zodiac. Each division, however, because of the precession of the equinoxes, now contains the constellation west of the one from which it took its name. Cf. sign of the zodiac.2. a circular or elliptical diagram representing this belt, and usually containing pictures of the animals, human figures, etc., that are associated with the constellations and signs.3. a circuit or round.[1350-1400; ME zodiaque < L zodiacus < Gk zoidiakòs (kýklos) signal (circle), equiv. to zóidi(on) animal sign (zô(ion) animal + -idion dim. suffix) + -akos -AC]
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The orbits of the Moon and the major planets (except Pluto) lie entirely within the zodiac. In astrology, each of 12 constellations along this circle is considered to occupy 1/12 (30°) of it. The positions of the Sun and planets when a person is born and their motion through these constellations are said to exert influence on his or her life, though precession of the equinoxes has shifted the constellations eastward and the Sun no longer passes through them on the traditional dates: Aries, the ram (March 21–April 19); Taurus, the bull (April 20–May 20); Gemini, the twins (May 21–June 21); Cancer, the crab (June 22–July 22); Leo, the lion (July 23–August 22); Virgo, the virgin (August 23–September 22); Libra, the balance (September 23–October 23); Scorpius (see Scorpio), the scorpion (October 24–November 21); Sagittarius, the archer (November 22–December 21); Capricornus (see Capricorn), the goat (December 22–January 19); Aquarius, the water bearer (January 20–February 18); Pisces, the fish (February 19–March 20).* * *
▪ astronomy and astrologyin astronomy and astrology, a belt around the heavens extending 9° on either side of the ecliptic, the plane of the earth's orbit and of the sun's apparent annual path. The orbits of the moon and of the principal planets also lie entirely within the zodiac. The 12 astrological signs of the zodiac are each considered to occupy 1/12 (or 30°) of its great circle. These signs no longer correspond to the astronomical constellations in which the sun actually appears. The constellations are irregular in size and shape, and the sun regularly passes through one constellation (Ophiuchus) that is not considered a member of the zodiac.Because most of the constellations through which the ecliptic passes represent animals, the ancient Greeks called its zone zōdiakos kyklos, “circle of animals,” or ta zōdia, “the little animals.” The size and number of zodiacal constellations varied in antiquity and became fixed only with the development of mathematical astronomy. The list below gives the constellations of the zodiac, with the dates of the sun's passage through them in the era when their boundaries were fixed. These dates are still used for the astrological signs, though precession of the equinoxes has shifted the constellations eastward; e.g., on January 1 the direction of the sun is now in Sagittarius instead of Capricornus. The history of the symbols is unknown; they seem to appear first in Greek manuscripts of the late Middle Ages.* * *
Universalium. 2010.