What you can expect from calibration
When calibrating a measuring instrument, the correlation between the input quantity and the output quantity is determined under specified conditions and then documented.
The input quantity is the physical quantity to be measured, e.g. force or pressure.
The output quantity is often the electrical or electronic output signal of the measuring instrument, although it can also be a reading.
Terms and definitions...
Calibration is often confused with other terms, or lumped together with terms that describe quite different processes:
Test refers to a test that establishes the extent to which a requirement is met.
Adjustment occurs when a measuring instrument is set up or balanced in order to eliminate the known systematic variations for the intended application.
Legal verification covers quality testing and rating in accordance with the verification specifications. This is prescribed, for example, to test equipment for pricing (shop scales, petrol pumps) or for medical products and is performed by Weights and Measures Boards.
Balancing the measuring chain is necessary in order to convert the known measurement properties of a transducer (typically obtained from calibration) to the correct settings at the measuring amplifier.