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.
Conventional quantity value
A quantity value attributed to a quantity by agreement for a given purpose — the conventional value of local gravity, or the conventional mass of a weight.
VIM (JCGM 200:2012) 2.12 · General
Correction
Compensation for an estimated systematic effect, applied additively or multiplicatively. The uncertainty of the correction itself must enter the budget.
VIM (JCGM 200:2012) 2.53 · General
Influence quantity
A quantity that, in a direct measurement, does not affect the quantity actually measured but does affect the relation between the indication and the result — ambient temperature is the classic example.
VIM (JCGM 200:2012) 2.52 · General
Measurand
The quantity intended to be measured. Specifying a measurand requires the kind of quantity and a description of the state of the phenomenon, body, or substance carrying it.
VIM (JCGM 200:2012) 2.3 · General
Measured quantity value
The quantity value representing a measurement result — the value actually obtained for the measurand in a given measurement.
VIM (JCGM 200:2012) 2.10 · General
Measurement
The process of experimentally obtaining one or more quantity values that can reasonably be attributed to a quantity, presupposing a description of the quantity, a procedure, and calibrated equipment.
VIM (JCGM 200:2012) 2.1 · General
Measurement accuracy
Closeness of agreement between a measured value and a true value of the measurand. A qualitative concept — a measurement is more accurate when it offers smaller error, but accuracy itself is not a number.
VIM (JCGM 200:2012) 2.13 · General
Measurement error
Measured quantity value minus a reference quantity value; comprises a systematic component and a random component.
VIM (JCGM 200:2012) 2.16 · General
Measurement method
A generic description of the logical organization of operations used in a measurement — substitution method, differential method, null method.
VIM (JCGM 200:2012) 2.5 · General
Measurement principle
The phenomenon serving as the basis of a measurement — thermoelectric effect for a thermocouple, Doppler shift for a radar gun.
VIM (JCGM 200:2012) 2.4 · General
Measurement procedure
A detailed description of a measurement according to a principle and method, based on a measurement model — detailed enough that a trained operator can perform it. The SOP is its documented form.
VIM (JCGM 200:2012) 2.6 · General
Measurement result
The set of quantity values attributed to a measurand together with any other available relevant information — generally a measured value with its measurement uncertainty.
VIM (JCGM 200:2012) 2.9 · General
Metrology
The science of measurement and its application — including all theoretical and practical aspects, whatever the uncertainty and field of application.
VIM (JCGM 200:2012) 2.2 · General
Nominal property
A property of a phenomenon, body, or substance that has no magnitude — the sex of a specimen, the color sequence of a resistor, an ISO country code. It can be examined and classified, but not measured.
VIM (JCGM 200:2012) 1.30 · General
Primary reference measurement procedure
A reference procedure used to obtain a result without relation to a standard for a quantity of the same kind — the route by which primary standards are realized.
VIM (JCGM 200:2012) 2.8 · General
Random measurement error
The component of measurement error that varies unpredictably in replicate measurements, characterized by a distribution usually summarized by its standard deviation.
VIM (JCGM 200:2012) 2.19 · General
Reference measurement procedure
A procedure accepted as providing results fit for assessing the trueness of values obtained from other procedures for the same kind of quantity.
VIM (JCGM 200:2012) 2.7 · General
Systematic measurement error
The component of measurement error that in replicate measurements remains constant or varies predictably. Known systematic errors are compensated by correction.
VIM (JCGM 200:2012) 2.17 · General
True quantity value
The quantity value consistent with the definition of the quantity. In practice unknowable; measurement estimates it with stated uncertainty.
VIM (JCGM 200:2012) 2.11 · General