Cusp forms are a special type of mathematical function found in the field of modular forms. They are defined on the upper half of the complex plane and have specific properties that make them useful in number theory and algebra. Unlike other modular forms, cusp forms vanish at the "cusps," which are points at infinity in the modular space. These forms play a crucial role in various areas of mathematics, including elliptic curves and automorphic representations. They are often studied for their connections to L-functions and their applications in solving problems related to partition theory and arithmetic geometry.