QIMT Glossary

Definitions of Metrology terms & phrases.

If you know of a term or phrase that belongs here, you can submit the term or phrase and associated definition by adding an entry. NOTE: All entries are reviewed and approved prior to being seen by others on the site.

Procedure for adding a Definition:

  1. Click on the "Add a New Entry" button.
  2. Under the first required field labeled 'Concept', enter the Metrology word or term.
  3. In the 'Description' Field, put the definition, don't forget to use the "DeWord" button to remove MS Word formatting if you are copying and pasting from MS Word; see lounge forum for note regarding this issue.
  4. Ignore the other entries and submit.

You can browse using the alphabet, or find a definition by searching for any term, or by any text within the definition itself. Or click on ALL to see all the posted definitions.

You can also start discussions by 'commenting' on a definition.cool

Use the little icon in the corner of the quote to comment.

Browse the glossary using this index

Special | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | ALL

Page:  1  2  3  (Next)



Southern African Development Community (SADC) Cooperation in Measurement Traceability.

Scale division

Part of a scale between any two successive scale marks.

Scale range

The set of values bounded by the extreme indications on an analogue measuring instrument.

Scale spacing

Distance between two successive adjacent scale marks measured along the same line as the scale length.


APEC Sub-committee on Standards and Conformance.

Secondary standard

Standard whose value is assigned by comparison with a primary standard of the same quantity.


Element in a measuring instrument or a measuring chain that is directly influenced by the measurand.

SI system

The international system of units, Le Syst

SI unit

A unit in the SI system.


Sistema Interamricano de Metrologia, Normalizaci


Slovensky Metrologicky Ustav, the national metrological institute of the Slovak Republic.


Sveriges Provnings- och Forskningsinstitut, the national metrological institute of Sweden.


Modulus of the difference between two limits of a nominal range.


The ability of a measuring instrument to maintain constant its metrological characteristics with time.


See Measuring standard.

standard deviation


"Measure of the unpredictability of a random variable, expressed as the average deviation of a set of data from its arithmetic mean and computed as the positive square root of the variance. Customarily represented by the lower-case Greek letter sigma (σ), it is considered the most useful and important measure of dispersion which has all the essential properties of the variance plus the advantage of being determined in the same units as those of the original data. Also called root mean square (RMS) deviation."

As per the ISO GUM, the standard deviation = the standard uncertainty for the given contributor.

Standard deviation, experimental

Parameters for a series of n measurements of the same measurand, characterises the dispersion of the results and is given by the formula for standard deviation.

Standard Reference Material,

see Reference Material, Certified.

Standard, compound

A set of similar material measures or measuring instruments that, through their combined use constitutes one standard called a compound standard.

Standard, transfer

Standard used as an intermediary to compare standards.

Standard, travelling

Standard, sometimes specially composed, for use in making comparisons between standards at different locations.


The input signal for a measuring system can be called a stimulus and the output signal can be called a response.

System of measurement units

A number of basic units and derived units defined in accordance with given rules for a given system of values.

System of units

Systematic error

Mean that would result from an infinite number of measurements of the same measurand carried out under repeatability conditions minus a true value of the measurand.

Page:  1  2  3  (Next)