1 Not dependent on or relative to anything else, e.g. absolute zero.
2 Denoting a temperature measured on an absolute scale, a scale of temperature based on absolute zero. The usual absolute scale now is that of thermodynamic temperature; its unit, the kelvin, was formerly called the degree absolute (°A) and is the same size as the degree Celsius. In British engineering practice an absolute scale with Fahrenheit-size degrees has been used: this is the Rankine scale.