Calibrator (noun)

1. A device or tool used to check, adjust, or set the accuracy or sensitivity of a measuring instrument.
2. A substance or solution used to check the accuracy of a scientific instrument.

Origin:

Late 17th century (in the sense "standard for measuring"): from latin calibrat- "made level", from the verb calibrare, from calx, calv- "chalk, limestone".

Examples:

1. The calibrator was used to check the accuracy of the scale.
2. The calibrator was used to adjust the sensitivity of the instrument.
3. The calibrator was used to set the accuracy of the instrument.
4. A substance was used as a calibrator to check the accuracy of the scientific instrument.
5. A solution was used as a calibrator to check the accuracy of the scientific instrument.