Cusp (astrology)

In astrology, a cusp refers to the dividing line between two signs of the zodiac or between two houses in a birth chart. It is the point where one astrological influence ends and another begins. Because a zodiac sign covers a 30-degree span, and the sun typically spends about a month in each sign, individuals born within a few days on either side of the traditional sign boundary are said to be "born on the cusp."

The significance of being "on the cusp" is a subject of debate among astrologers. Some believe that individuals born on a cusp may exhibit traits of both signs adjacent to the cusp. For example, someone born on the Aries-Taurus cusp might be seen as possessing both the fiery energy of Aries and the grounded sensuality of Taurus. Others argue that a planet can only be in one sign at a time, and that a precise birth chart calculation is necessary to determine the exact sign placement.

Similarly, house cusps mark the beginning of each of the twelve houses in a birth chart. Each house represents a different area of life, such as career, relationships, or home. The planetary placements within each house and the sign on the cusp of each house influence how that area of life manifests. The degree of the zodiac on the cusp of each house is calculated based on the birth time and location.