Absolute zero

From Glossary of Meteorology

absolute zero

The zero point of the Kelvin temperature scale, of fundamental significance in thermodynamics and statistical mechanics.

It is the linearly extrapolated temperature at which the volume of an ideal gas at constant pressure would vanish. All real gases become liquid or solid at sufficiently low temperatures and maintain a finite volume. Absolute zero on the Kelvin scale corresponds to -273.15°C.