Knowledge
Metrology Dictionary
The complete VIM vocabulary — all numbered concepts of JCGM 200:2012 as faithful paraphrases with clause citations — plus clearly labeled practice terms from the GUM, ILAC, ISO and NIST guidance.
Adjustment of a measuring system
The set of operations carried out on a measuring system so that it provides prescribed indications corresponding to given quantity values. Adjustment changes the instrument; calibration afterwards re-establishes its relation to standards.
VIM (JCGM 200:2012) 3.11 · Calibration
Calibration
The operation that, under specified conditions, first establishes a relation between values (with uncertainties) provided by measurement standards and corresponding indications (with uncertainties), and second uses that information to obtain results from indications. Calibration is not adjustment.
VIM (JCGM 200:2012) 2.39 · Calibration
Calibration curve
The expression of the relation between indication and corresponding measured quantity value established by calibration — the diagram's central line, without the uncertainty strip.
VIM (JCGM 200:2012) 4.31 · Calibration
Calibration diagram
A graphical expression of the relation between indication and corresponding measurement result, showing the strip of estimated uncertainty around the relation.
VIM (JCGM 200:2012) 4.30 · Calibration
Calibration hierarchy
The sequence of calibrations from a stated reference to the final measuring system, each calibration depending on the previous one; uncertainty necessarily grows down the chain.
VIM (JCGM 200:2012) 2.40 · Calibration
Calibrator
A measurement standard used in calibration — in some fields, a device or material whose assigned value is transferred to the instrument under calibration.
VIM (JCGM 200:2012) 5.12 · Calibration
Metrological comparability of measurement results
Comparability of results traceable to the same reference — what shared traceability buys: results that can be meaningfully compared even from different labs and methods.
VIM (JCGM 200:2012) 2.46 · Calibration
Metrological traceability
The property of a result whereby it can be related to a stated reference — usually the SI — through a documented unbroken chain of calibrations, each contributing to the uncertainty.
VIM (JCGM 200:2012) 2.41 · Calibration
Metrological traceability chain
The sequence of standards and calibrations used to relate a result to a stated reference — the concrete path behind a traceability claim.
VIM (JCGM 200:2012) 2.42 · Calibration
Metrological traceability to a measurement unit
Traceability whose stated reference is the definition of a unit through its practical realization — "traceable to the SI" in its precise sense.
VIM (JCGM 200:2012) 2.43 · Calibration
Verification
Provision of objective evidence that a given item fulfils specified requirements — e.g. that an instrument performs within its maximum permissible errors. A pass/fail attestation, distinct from calibration.
VIM (JCGM 200:2012) 2.44 · Calibration
Zero adjustment of a measuring system
Adjustment so that the system provides a null indication corresponding to a zero value of the quantity to be measured.
VIM (JCGM 200:2012) 3.12 · Calibration