absolute zero

The lowest possible temperature. By its definition in physics, temperature has the character of an average energy. For instance, the temperature of gas is proportional to the average kinetic energy of the moving molecules or atoms. In this case, absolute zero would be reached when the gas particles do not move at all.

On the usual temperature scales, absolute zero is at -459.67 degrees Fahrenheit or -273.15 degrees Celsius. By definition of the Kelvin scale, absolute zero is at zero Kelvin.