Astrology is how the planets and their movements in the sky affect us, as individuals, on earth. Each planet symbolizes a certain force or energy; each of the 12 astrological signs represents a different mode or style in which that energy is expressed. Astrology refers to any of several systems, traditions or beliefs in which knowledge of the apparent positions of celestial bodies is held to be useful in understanding, interpreting, and organizing knowledge about human affairs and events on Earth. A practitioner of astrology is called an astrologer or, less often, an astrologist. The etymological origin of the word "astrology" is the Greek word asta, derived from st, astron, "star" and , logos, which has a variety of meanings generally related to "systematic thought or speech". Logos is written in English as the suffix, -ology, denoting a "study or discipline". Although the two fields share a common origin, modern astronomy as practiced is not to be confused with astrology. While astronomy is the study and observation of celestial objects and their movements through space, astrology is the study of the supposed correlation of those objects with earthly affairs. There is no widely accepted evidence that astrology as a system has a falsifiable, scientific basis though individual astrological predictions may be subject to disproof. Where it has been tested, astrology has shown a consistent lack of predictive power.
A horoscope is a natal chart, a specific type of horoscope created for the moment of a person's birth.Central to horoscopic astrology is the calculation of a horoscope, or astrological chart. This is a diagrammatic representation in two dimensions of the celestial bodies' apparent positions in the heavens from the vantage of a location on Earth at a given time and place. The horoscope of an individual's birth is called a natal chart. In ancient Hellenistic astrology the rising sign or ascendant demarcated the first celestial house of a horoscope, and the word for the ascendant in Greek was horoskopos. This is the word that the term "horoscope" derives from and in modern times it has come to be used as a general term for an astrological chart as a whole. Other commonly used names for the horoscope/natal chart in English include natus, birth-chart, astrological chart, astro-chart, celestial map, sky-map, star-chart, nativity, cosmogram, vitasphere, soulprint, radical chart, radix, or simply chart, among others. The zodiac versus constellations The path of the sun across the heavens as seen from Earth during a full year is called the ecliptic. This, and the nearby band of sky followed by the visible planets, is called the zodiac. The majority of Western astrologers base their work on the tropical zodiac, which evenly divides the ecliptic into 12 even segments of 30 degrees each with the start of the Zodiac (Aries 0°) being the Sun's position at the northward or March equinox. The zodiacal signs in this system bear no relation to the constellations of the same name but stay aligned to the months and seasons. All Jyotish (Hindu) and a few Western astrologers use the sidereal zodiac, which uses the same evenly divided ecliptic but which approximately stays aligned to the positions of the observable constellations with the same name as the zodiacal signs.