The point in a one-component system at which the temperature and pressure of three phases are in equilibrium.PAC, 1994, 66, 577 (Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations 1994)) on page 593, Punkt ühekomponentse süsteemi olekudiagrammil), kus kolme faasi rõhk ja temperatuur on tasakaalus
