Ancient observers of the heavens developed elaborate systems of explanation based on the movements of the sun, moon, and planets through the constellations of the zodiac, for predicting events and for casting horoscopes. By 1700 astrology had lost intellectual credibility in the West, but continued to have popular appeal. Modern astrology is based on that of the Greeks, but other systems are extant, e.g. that of China
late Middle English: from Old French astrologie, from Latin astrologia, from Greek, from astron 'star'