1. The aspect of the planets and stars at a given moment, as the moment of a person's birth, used in astrology: A horoscope is an astrologer's description of an individual's personality and future based on the position of the planets in relation to the sign of the zodiac under which the person was born.
2. A diagram of the heavens showing the relative position of planets and the signs of the zodiac, for use in calculating births, foretelling events in a person's life, etc.: A horoscope can be a prediction of future events or advice for future behavior based on the diagram described in the previous definition.