Universality classes are categories that group systems exhibiting similar behavior under certain conditions, despite differences in their microscopic details. These classes arise in various fields, such as physics, mathematics, and biology, where systems can show the same critical phenomena, like phase transitions, regardless of their specific components. For example, systems in the same universality class may share properties like scaling laws and critical exponents. This means that when studying phenomena like magnetism or fluid dynamics, researchers can apply the same theoretical frameworks to different materials or situations, simplifying complex analyses and enhancing our understanding of diverse systems.