Definition of standard temperature

1. 1 : defined as 21 degrees C ± 5 degrees C (70 degrees F ± 10 degrees F). [SEMI F4-90] 2 : in the calibration of mass flow devices, the temperature, in degrees Celsius, specified as a reference for measurement and comparison. In the semiconductor industry, this temperature is defined as 0.0 degrees C. [SEMI E29-93]