What is a calibration?
By ISO/IEC GUIDE 99:2007, calibration is an operation that establishes a relation between the quantity values and corresponding indications.
A calibration may be expressed by a statement, calibration function, calibration diagram, calibration curve, or calibration table. According to the definition given in the International Vocabulary of Metrology (VIM4) calibration also requires the determination of the uncertainties associated with the measurements performed. Calibration can be executed on a measuring instrument or system, or a measurement standard.