Astrology is the study of the relationship between the stars and other heavenly bodies and the effects they have on one's personality and one's future. It is used mostly for divination and learning more about oneself and others.
Your horoscope is an example of western astrology. Western astrology depends on the twelve signs of the Zodiac.
Astrology has been around since ancient times, around 3000 B.C., when people observed the relationships between things in space, such as the stars and planets, and the changes on the earth.