Cardinal sign (astrology) Cardinal sign (astrology) The practice of astrology recognizes four cardinal signs of the zodiac: Aries, Cancer, Libra, and Capricorn — sometimes called reacting signs. It associates those people born "under" one of these with certain human behaviors and traits like being active, self-motivated, insightful and ambitious. The word "cardinal" originates from the Latin word for "important," since they each mark the turning point of a temperate season. They were called "moveable" by traditional astrologers because, as Bonatti says, the "air" changes when the Sun enters each of these signs, bringing a change of season. Sometimes the word "cardinal" is confused
Zodiac late Antiquity, by which time Ptolemy's influence was widely established. Ptolemy clearly explained the theoretical basis of the western zodiac as being a tropical coordinate system, by which the zodiac is aligned to the equinoxes and solstices, rather than the visible constellations that bear the same names as the zodiac signs. The Hindu zodiac uses the sidereal coordinate system, which makes reference to the fixed stars. The Tropical zodiac (of Mesopotamian origin) is divided by the intersections of the ecliptic and equator, which shifts in relation to the backdrop of fixed stars at a rate of 1° every 72 years,