Astrological signs represent twelve equal segments or divisions of the zodiac. According to astrological superstition, celestial phenomena reflect or govern human activity on the principle of "as above, so below", so that the twelve signs at the same time are held to represent twelve basic personality types or characteristic modes of expression.^[1]

In Western and Indian astrology, the twelve signs are associated with constellations, while in Chinese astrology there is no connection with constellations, as it is simply the line of the equator that is divided into twelve equal segments.

In Western and Indian astrology, the emphasis is on space, and the movement of the sun, moon and planets in the sky through each of the zodiac signs. In Chinese astrology, by contrast, the emphasis is on time, with the zodiac operating on cycles of years, months, and hours of the day. A common feature of all three traditions however, is the significance of the ascendant or rising sign, namely the zodiac sign that is rising (due to the rotation of the earth) on the eastern horizon at the moment of a person's birth.

The three main traditions of astrology, the Western, Indian and Chinese, share the same fundamental idea of a twelve sign zodiac with the signs divided into four basic types. It is possible to match up the twelve signs across the traditions, and despite differences, a basic similarity can be seen in their characteristics. The following table shows the twelve signs and their sub-division into four categories as they correspond across the three traditions: