Multicritical point

Multicritical points are special points in the parameter space of thermodynamic or other systems with a continuous phase transition. At least two thermodynamic or other parameters must be adjusted to reach a multicritical point. At a multicritical point the system belongs to a universality class different from the "normal" universality class.

A more detailed definition requires concepts from the theory of critical phenomena, a branch of physics that reached a very satisfying state in the 1970s.