QIMT Glossary



Definitions of Metrology terms & phrases.

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Browse the glossary using this index

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A

Accredited laboratory

Laboratory with 3rd party approval of the laboratory’s technical competence, the quality assurance system it uses, and its impartiality.

Accuracy class

Class of measuring instruments that meet certain metrological requirements intended to keep errors within specified limits.

Accuracy of a measuring instrument

The ability of a measuring instrument to give responses close to a true value.

Accuracy of measurement

Closeness of the agreement between the result of a measurement and a true value of the measurand.

Adjustment of a measuring instrument

Process that brings a measuring instrument into a functional condition. corresponding to the purpose for which it is used.

APEC

Asia-Pacific Economic Cooperation.

APLAC

Asia-Pacific Laboratory Accreditation Cooperation

APLMF

Asia-Pacific Legal Metrology Forum

APMP

Asia-Pacific Metrology Programme

Artefact

An object fashioned by human hand. Examples of artefacts made for taking measurements are a weight and a measuring rod.

B

Basic unit

(for measurement) Unit of measurement for a basic magnitude in a given system of magnitudes.

BIPM

Bureau International des Poids et Mesures

BNM

Bureau National de Métrologie, the national metrological institute of France.

C

Calibration

Set of operations that establish, under specified conditions, the relationship between values of quantities indicated by a measuring instrument or measuring system, or values represented by a material measure or a reference material and the corresponding values realised by standards.

Calibration certificate

Result(s) of a calibration can be registered in a document sometimes called a calibration certificate or a calibration report.

Calibration history, measuring equipment

Complete registration of the results from the calibration of a piece of measuring equipment, or measuring artefact, over a long period of time, to enable the evaluation of the long-term stability of the piece of equipment or the measuring artefact.

Calibration interval

Time interval between two consecutive calibrations of a measuring instrument.

Calibration report

Result(s) of a calibration can be registered in a document sometimes called a calibration certificate or a calibration report.

CCAUV

Consultative Committee for Acoustics, Ultrasound and Vibrations. Established 1998.

CCEM

Consultative Committee for Electricity and Magnetism. Established 1927.

CCL

Consultative Committee for Length. Established 1952.

CCM

Consultative Committee for Mass and related quantities. Established 1980.

CCPR

Consultative Committee for Photometry and Radiometry. Established 1933.

CCQM

Consultative Committee for Amount of Substance - Metrology in chemistry. Established 1993.

CCRI

Consultative Committee for Ionising Radiation. Established 1958.

CCT

Consultative Committee for Thermometry. Established 1937.

CCTF

Consultative Committee for Time and Frequency. Established 1956.

CCU

Consultative Committee for Units. Established 1964.

CEM

Centro Español de Metrología, the national metrological institute of Spain.

CEN

Comité Européene de Normalisation. European standardisation organisation.

CGPM

Conférence Générale des Poids et Mesures. Held for the first time in 1889. Meeting every 4th year.

Check standard

Working standard routinely used to ensure that measurements are made correctly.

CIPM

Comité Internationale des Poids et Mesures.

CIPM MRA

CMC

Calibration and Measurement Capabilities

CMI

Czech Metrology Institute, the national metrological institute of the Czech Republic.

Compound standard

Set of similar material measures or measuring instruments that, through their combined use, constitutes a standard.

Conformity assessment

An activity that provides demonstration that specified requirements relating to a product, process, system, person or body are fulfilled, i.e. testing, inspection, certification of products, personnel and management systems.

Conventional true value (of a quantity)

Value attributed to a particular quantity and accepted, sometimes by convention, as having an uncertainty appropriate for a given purpose. Sometimes called “assigned value”, “best estimate of the value”, “conventional value”, or “reference value”.

COOMET

Euro-Asian cooperation of national metrological institutions.

Correction factor

Factor by which the uncorrected measuring result is multiplied to compensate for a systematic error.

Correction value

Value which added algebraically to the uncorrected result of a measurement compensates for a systematic error.

CRM

See Reference material, certified.

CSIR - NML

National Metrology Laboratory, the national metrological instituteSouth Africa.

CSIRO NML

The national metrological institute of Australia. The National Measurement Laboratory NML is a National Facility within the Commonwealth Scientific and Industrial Research Organisation CSIRO.

D

Dead band

Maximum interval through which a stimulus may be changed in both directions without producing a change in response of a measuring instrument.

Derived unit

(of measurement)

Detector

A device or substance that indicates the presence of a phenomenon without necessarily providing a value of an associated quantity. E.g. litmus paper.

Deviation

Value minus its reference value.

DFM

Dansk Institut for Fundamental Metrologi. The national metrological instituteDenmark.

Drift

Slow change of a metrological characteristic of a measuring instrument.

E

EA

European Co-operation for Accreditation, formed by the amalgamation of EAL (European Co-operation for Accreditation of Laboratories) and EAC (European Accreditation of Certification) in November 1997.

EAC

See EA.

EAL

See EA.

EOTC

The European Organisation for Conformity Assessment.

EPTIS

European Proficiency Testing Information System

Error (for a measuring instrument), largest permissible

Extreme values for an error permitted by specifications, regulations, etc. for a given measuring instrument.

Error (in a measuring instrument), systematic

Systematic indication error in a measuring instrument.

Error limit (for a measuring instrument

Extreme values for an error permitted by specifications, regulations, etc. for a given measuring instrument.

EUROLAB

Voluntary co-operation between testing and calibration laboratories in Europe.

EUROMET

Co-operation between national metrological institutes in and the European Commission.

F

Fundamental Metrology

G

General conference on measures and weights

See CGPM.

GLP

Good Laboratory Practice. Accrediting bodies approve laboratories in accordance with the GLP rules of OECD.

GUM

Guide to the Expression of Uncertainty in Measurement. Published by BIPM, IEC, ISO, OIML and IFCC (International Federation of Clinical Chemistry), IUPAC (International Union of Pure and Applied Chemistry) and IUPAP (International of Pure and Applied Physics).

H

History, measuring equipment

See calibration history.

I

IEC

International Electrotechnical Commission.

ILAC

International Laboratory Accreditation Coorperation

Indication (of a measuring instrument)

Value of a (measurable) quantity provided by a measuring instrument.

Influence quantity

Quantity that is not the measurand (quantity subject to measurement) but that affects the result of the measurement.

Instrument constant

Coefficient by which the direct indication of a measuring instrument must be multiplied to give the indicated value of the measurand or be used to calculate the value of the measurand.

International (measuring) standard

Standard recognised by international agreement as suitable for international use as a basis for determining the value of other standards for a given magnitude.

IPQ

Instituto Português da Qualidade, the national metrological institute of Portugal.

IRMM

Institute for Reference Materials and Measurements, Joint Research Centre under the European Commission.

ISO

International Organisation for Standardisation.

ISO/IEC 17025

ISO/IEC 17025 is the main standard used by testing and calibration laboratories. Originally known as ISO/IEC Guide 25, ISO/IEC 17025 was initially issued by the International Organization for Standardization in 1999. There are many commonalities with the ISO 9000 standard, but ISO/IEC 17025 adds in the concept of competence to the equation. And it applies directly to those organizations that produce testing and calibration results.

Since its initial release, a second release was made in 2005 after it was agreed that it needed to have its quality system words more closely aligned with the 2000 version of ISO 9001...for more info...CLICK HERE.

ISO/IEC17025

IUPAP

The International Union of Pure and Applied Physicists

J

JCRB

Joint Committee of the BIPM

Justervesenet

The national metrological institute of Norway.

L

Legal metrology

M

Maintenance of a measurement standard

Set of measures necessary to preserve the metrological characteristics of a measurement standard within appropriate limits.

Market surveillance

used to enforce legal metrology

Material measure

Device intended to reproduce or supply, in a permanent manner during its use, one or more known values of a given quantity. e.g. a weight, a volume measure, a gauge block, or a reference material.

Maximum permissible errors (of a measuring instrument)

Extreme values of an error permitted by specifications, regulations, etc. for a given measuring instrument.

Measurand

Particular quantity subject to measurement.

Measure, material

Device intended to take a measurement, alone or in conjunction with supplementary devices.

Measurement

Set of operations for the purpose of determining the value of a quantity.

Measurement procedure

Set of operations, described specifically, used in the performance of particular measurements according to a given method.

Measurement standard, etalon

Material measure, measuring instrument, reference material or measuring system intended to define, realise, conserve or reproduce a unit or one or more values of a quantity to serve as a reference.

Measurement standard, international

Standard recognised by an international agreement to serve internationally as the basis for assigning values to other standards of the quantity concerned.

Measurement standard, maintenance

Set of operations necessary to preserve the metrological characteristics of a measurement standard within appropriate limits.

Measurement standard, national

Standard recognised by a national decision to serve in a country as the basis for assigning values to other standards of the quantity concerned.

Measurement Uncertainty

"A parameter associated with the result of a measurement, that characterizes the dispersion of the values that could reasonably be attributed to the measurand."

Measurement unit

See Unit of measurement. A particular quantity, defined and adopted by convention, with which other quantities of the same kind are compared in order to express their magnitudes relative to that quantity.

Measuring chain

Series of elements of a measuring instrument or measuring system that constitutes the path of the measurement signal from the input to the output.

Measuring error

Result of a measurement minus a true value of the measurand.

Measuring error, absolute

When it is necessary to distinguish “error” from “relative error” the former is sometimes called “absolute error of measurement”.

Measuring instrument

Device intended to be used to make measurements, alone or in conjunction with supplementary devices.

Measuring range

Set of values of measurands for which the error of a measuring instrument is intended to lie within specified limits.

Measuring result

Value attributed to a measured measurand arrived at by measurement.

Measuring system

Complete set of measuring instruments and other equipment assembled to carry out specified measurements.

Measuring unit off-system

Unit of measurement that does not belong to a given system of units.

METAS

Swiss Federal Office of Metrology and Accreditation, the national metrological institute of Switzerland.

Method of measurement

Logical sequence of operations, described generically, used in the performance of measurements.

Metre Convention

International convention established in 1875 for the purpose of ensuring a globally uniform system of measuring units. In 2003 there were 51 member nations.

MetreConvention

International convention established in 1875 for the purpose of ensuring a globally uniform system of measuring units. In 2003 there were 51 member nations.

Metric system

A measuring system based on metres and kilograms. Subsequently developed into the SI system.

Metrological subject field

Metrology is divided into 11 subject fields.

Metrologist

One who is a specialist in one or more metrology disciplines. The informal categories associated with being a metrologist are:

Metrology

From the Greek word “metron” = measurement. The science of measurement.

Metrology Engineer

One who capable in the design of measurement processes to meet specified capabilities and/or facilitates the development of the measurement methods used in measurement processes. This requires an understanding of the physics involved and the uncertainty contributors that are significant to the process capability.

Definition created by QIMT

Metrology Technician

One who capable in the performance of measurement processes of one or more metrology disciplines. This requires a basic understanding of the physics involved and how to guard against the undesirable influences the operator can have on the measurement result.

Definition created by QIMT

Metrology, fundamental

There is no international definition of the expression “fundamental metrology” but this expression stands for the most accurate level of measurement within a given discipline.

Metrology, industrial

Ensures appropriate function of the measuring instruments used in industry as well as in production and testing processes.

Metrology, legal

Ensures accuracy of measurement where measured values can affect health, safety, or the transparency of financial transactions.

Metrology, scientific

Endeavours to organise, develop and maintain measuring standards.

MID

The Measuring Instruments Directive

MIRS

Standards and Metrology Institute of Slovenia, the national metrological institute of Slovenia.

MKSA system

A system of measurement units based on Metres, Kilograms, Seconds and Amperes. In 1954 the system was extended to include the Kelvin and the Candela. It was then given the name “SI system”.

MRA

see Mutual Recognition Arrangement.

Mutual Recognition Arrangement, CIPM

MRA for national measurement standards and for calibration and measurement certificates issued by NMIs.

N

National measurement standard

Standard recognised by a national decision to serve in a country as the basis for assigning values to other standards of the quantity concerned.

NIST

National Institute of Standards and Technology, the national metrological institute of the USA.

NMI

Often-used English abbreviation for the national metrological institute of a country.

NMi-VSL

Nederlands Meetinstituut - Van Swinden Laboratorium, the national metrological institute of the Netherlands.

Nominal value

NPL

National Physical Laboratory, the national metrological institute of UK.

NRC

National Research Council, Institute for National Measurement Standards, the national metrological institute of Canada.

O

OAS

Organization of American States.

OIML

Organisation Internationale de M

P

Performance testing

(laboratory) Determination of the testing capability of a laboratory, by comparing tests performed between laboratories.

Preventive measures

(opposite of repressive measure) are used for market surveillance and are taken before marketing a measuring instruments, i.e. the instrument has to be type-approved and verified.

Primary laboratory

Laboratory that performs internationally adopted fundamental metrological research and which realises and maintains standards at the highest international level.

Primary method

A method of the highest metrological quality which when implemented can be described and understood completely, and for which a complete uncertainty budget can be provided in SI units, the results of which can therefore be accepted without reference to a standard for the magnitude being measured.

Primary reference material

Primary standard

Standard that is designated or widely acknowledged as having the highest metrological qualities and whose value is accepted without reference to other standards of the same quantity

Principle of measurement

The scientific foundation of a method of measurement.

Prototype

Artefact that defines a unit of measurement. The kilogram prototype (1 kg weight) in Paris is today the only prototype in the SI system.

PTB

Physikalisch-Technische Bundesanstalt, the national metrological institute of Germany.

PTS

Proficiency testing schemes

Q

Quantity (measurable)

Attribute of a phenomenon, body or substance that may be distinguished qualitatively and determined quantitatively.

Quantity derived

Quantity defined, in a system of quantities, as a function of base quantities of that system.

Quantity dimension

Expression that represents a quantity of a system of quantities as the product of powers of factors that represent the basic quantities of the system.

R

Random error

Result of a measurement minus the mean that would result from an infinite number of measurements of the same measurand carried out under repeatability conditions.

Reference conditions

Conditions of use prescribed for testing the performance of a measuring instrument or for the intercomparison of results of measurements.

Reference material (CRM), certified

Reference material, accompanied by a certificate, which has one or more properties whose value is certified by a procedure that establishes traceability to the accurate realisation of the unit in which the values of the properties are expressed, and for which each certified value is accompanied by a stated uncertainty with a given level of confidence.

Reference material (RM)

Material or substance one or more of whose property values are sufficiently homogenous and well established to be used for the calibration of an apparatus, the assessment of a measurement method, and for assigning values to materials.

Reference material, primary

Reference material that has the highest metrological qualities and whose value is determined by the use of a primary method.

Reference standard

In general the standard of the highest metrological quality which is accessible at a given location or in a given organisation, and from which measurements taken at the locality are derived.

Reference values

Normally part of the reference conditions of an instrument. See also Values, determined.

Relative error

Error of measurement divided by a true value of the measurand.

Repeatability (of a measuring instrument)

The ability of a measuring instrument to give, under defined conditions of use, closely similar responses for repeated applications of the same stimulus.

Repeatability (of results of measurements)

Closeness of the agreement between the results of successive measurements of the same measurand carried out under the same conditions of measurement.

Repressive measure

(opposite of preventive measure) used in market surveillance to reveal any illegal usage of a measuring instrument.

Reproducibility

(of results of measurements) Closeness of agreement between the results of measurements of the same measurand carried out under changed conditions of measurement.

Response

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

Result, corrected

Measuring result after correction for systematic error.

RMO

Regional Metrology Organisation

S

SADCMET

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.

SCSC

APEC Sub-committee on Standards and Conformance.

Secondary standard

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

Sensor

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.

SIM

Sistema Interamricano de Metrologia, Normalizaci

SMU

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

SP

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

Span

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

Stability

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

Standard

See Measuring standard.

standard deviation

Statistics:

"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.

Stimulus

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

See System of measurement 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.

T

TBT

Technical Barrier to Trade.

Testing

Technical procedure consisting of the determination of one or more characteristics of a given product, process service, in accordance with a specified procedure.

Threshold, resolution capability (discrimination)

Largest change in a stimulus that produces no detectable change in the response of a measuring instrument, the change in the stimulus taking place slowly and monotonically.

Traceability

Property of the result of a measurement or the value of a standard whereby it can be related to stated references, usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties.

Traceability chain

The unbroken chain of comparisons is defined under Traceability.

Transfer equipment

The description “transfer equipment” should be used when the intermediate link is not a standard.

Transfer standard

Standard used as an intermediary to compare standards.

Travelling standard

True value (of a quantity)

The indefinite form rather than the definite form is used in connection with true value, in that there can be many values that are consistent with the definition of a particular quantity.

U

Uncertainty of measurement

Parameter, associated with the result of a measurement that characterises the dispersion of values that could reasonably be attributed to the measurand. The estimation of uncertainty in accordance with GUM guidelines is usually accepted.

Unit (of measurement)

Particular quantity, defined and adopted by convention, with which other quantities of the same kind are compared in order to express their magnitudes relative to that quantity.

Unit of measurement (derived) coherent

Derived unit of measurement that can be expressed as the product of basic units in powers with the proportionality coefficient 1.

V

Value (of a measurand), transformed

Value of a measuring signal that represents a given measurand.

Value (of a quantity)

Magnitude of a particular quantity generally expressed as a unit of measurement multiplied by number.

Value, nominal

Rounded or approximate value of a characteristic of a measuring instrument that provides a guide to its use.

Values, derived

Conditions for use intended to keep the metrological characteristics of a measuring instrument specified limits.

VIM

International Vocabulary of basic and general terms in Metrology.

W

WebOps™

WebOps™ is short for "Web-based interactive training workshOps".

WebOps™ are:

highly interactive and customized to the particular clients needs, with the objective of providing training as needed, while completing actual work as delineated on the client submitted "Task List". Sort of a combination of training customized to the needs of the participants, along with guidance and hands-on completion of tasks needing performed by the laboratory; a modernized variation of OJT (On the Job Training).

WebOps™ mirrors the use of "Webinar" which is short for "Web-based seminar".
WebOps™ differ from Webinars, in numerous ways;

WebOps™ ares:
  1. Used to provide interactive training, tutoring, remote project management, guidance and technical assistance.
  2. Objective based, with each session having a defined objective, often delineated to address the client's "Task to be Completed List".
  3. Often part of a project management service and limited to the personnel involved.
  4. Customized to the needs of a particular client, and therefore nearly always private.
  5. Highly interactive with the pace controlled by the participants.
  6. Scheduled as needed and/or desired by the client, with no cancellation fees, until all objectives are met.
  7. Flexible in session duration and may consist of multiple sessions during the completion of a particular project.
WebOps™ is a trademark of the Quametec Corporation.
Source: QIMT

Working range

Set of values of measurands for which the error of a measuring instrument is intended to lie specified limits.

Working standard

Standard normally used routinely to calibrate or check material measures, measuring instruments reference materials.

WTO

World Trade Organisation.

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