A horoscope is an astrological chart or diagram representing the positions of the Sun, Moon, planets, astrological aspects, and sensitive angles at the time of an event, such as the moment of a person's birth. The word horoscope is derived from Greek words hõra and scopos meaning "time" and "observer" (horoskopos, pl. horoskopoi, or "marker(s) of the hour"). Other commonly used names for the horoscope in English include natal chart, astrological chart, astro-chart, celestial map, sky-map, star-chart, cosmogram, vitasphere, radical chart, radix, chart wheel, or simply chart. It is used as a method of divination regarding events relating to the point in time it represents, and it forms the basis of the horoscopic traditions of astrology.