@wikipedia

A property of a Pure Substance represented by the end point $//<![CDATA[ \begin{array}{l}(T_c, P_c)\end{array} //]]>$ of a Vapour Liquid Equilibrium (VLE) curve above which the liquid and gas state of a Pure Substance do not have a distinct boundary (see Fig. 1).

It is characterized by critical temperature  $//<![CDATA[ \begin{array}{l}T_c\end{array} //]]>$ and critical pressure  $//<![CDATA[ \begin{array}{l}P_c\end{array} //]]>$ , both being a material property.

See also

Natural Science / Physics / Thermodynamics / Thermodynamic system / Thermodynamic equilibrium / Phase Equilibrium /  Vapour Liquid Equilibrium (VLE)

[ State of matter ][ Pure substance ] [ Сritical Temperature T_c ] [ Critical Pressure (P_c) ]

[ Mixtures ][ Fluid Mixtures ] [ Pseudo-Critical Point (Tc, Pc) ]