A "Universality Class" refers to a group of systems that exhibit similar behavior and properties near critical points, despite differences in their microscopic details. This concept is often used in fields like statistical mechanics and condensed matter physics to categorize phase transitions, such as those seen in ferromagnets or liquid-gas systems. Systems within the same universality class share critical exponents and scaling laws, which describe how physical quantities change as they approach the transition point. This means that even if the systems are fundamentally different, their large-scale behavior can be predicted using the same mathematical framework, highlighting the underlying principles of phase transitions.