Thermodynamic temperature

Thermodynamic temperature is a measure, in kelvins (K), proportional to the thermal energy of a given body at equilibrium. Thermodynamic temperature provides a 'natural' scale of temperature for thermodynamics, with a uniquely defined zero point at absolute zero.

A temperature of 0 K is called "absolute zero," and coincides with the minimum molecular activity (i.e., thermal energy) of matter.

Thermodynamic temperature was formerly called "absolute temperature."

In practice, the International Temperature Scale of 1990 (ITS-90) serves as the basis for high-accuracy temperature measurements in science and technology.

Source: from Federal Standard 1037C