In astrology, a "cusp" refers to the transitional period between two zodiac signs. When someone is born on a cusp date, they may exhibit traits from both signs. For example, if a person is born on the cusp of Gemini and Cancer, they might show the sociable nature of Gemini along with the emotional depth of Cancer. This blending of characteristics can make cusp individuals unique and complex. Cusps can also apply to other areas, such as in geometry, where a cusp is a point where a curve meets itself or changes direction sharply. In both contexts, cusps represent a boundary or threshold, highlighting the idea of duality and transition.