1) Thermodynamics: Describing a condition in which a substance has
a temperature or pressure above its critical value of temperature or pressure.
Fr.: fluide supercritique
A fluid that is at a temperature and pressure above its thermodynamic critical point. In these conditions the substance acquires unique characteristics of density and mobility. Supercritical fluids exist deep inside some planets; for example, there is supercritical water deep inside the Earth.