The temperature and pressure at which the liquid and vapour intensive properties (density,
heat capacity, etc.) become equal. It is the highest temperature (
critical temperature) and pressure (
critical pressure) at which both a gaseous and a liquid phase of a given compound can coexist.
Source:
PAC, 1990, 62, 2167
(Glossary of atmospheric chemistry terms (Recommendations 1990))
on page 2183
PAC, 1993, 65, 2397
(Nomenclature for supercritical fluid chromatography and extraction (IUPAC Recommendations 1993))
on page 2399