INTERNATIONAL VOCABULARY OF METROLOGY

Metrology Terms

These metrology terms represent only a portion of the extensive vocabulary in metrology. Metrology is a critical discipline in science, engineering, manufacturing, and various industries, ensuring accuracy and reliability in measurements and processes.

The International Vocabulary of Metrology – Defines basic and general concepts and associated terms (VIM) 3^rd edition. According to the VIM, “In general, a vocabulary is a “terminological dictionary which contains designations and definitions from one or more specific subject fields”

(ISO 1087-1:2000, 3.7.2). The present Vocabulary pertains to metrology, the “science of measurement and its application”.

Metrology Terms

Term	Definition
Accuracy	The degree of closeness between a measured value and the true or accepted value.
Calibration	The comparison of an unknown to a known reference. The process of adjusting or comparing a measuring instrument or system to a known standard to ensure its accuracy.
International System of Units (SI)	The modern metric system of measurement, based on seven base units and their derived units, is used internationally.
Measurement	The process of quantifying an attribute of an object or phenomenon using a specific unit.
Metrologist	A person who specializes in the science of measurement and metrology.
Metrology	The science of measurement
Metrology Laboratory	A controlled environment where precision measurements are performed using calibrated equipment.
Traceability	An unbroken chain of calibrations relating to a recognized national or international standard through a chain of comparisons to an SI unit.
Measurement Uncertainty (MU)	“non-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand, based on the information used.” VIM, 3.9, measurement uncertainty (2012 updates)
Measurand	A “quantity intended to be measured” VIM
Precision	The degree of consistency or reproducibility of measurements when repeated under similar conditions.
SI Unit	The international system of units, comprised of 7 base units
SI Derived Unit	22 derived units of measure, derivatives of SI base units.
Standard	A known, agreed-upon value or reference is used as a basis for comparison in metrology.
Tolerance	The allowable deviation or variation from a specified dimension or value in a measurement.
Unit of Measurement	A defined quantity, such as length, mass, or time, is used as a standard for measuring other quantities of the same kind.

Metrology Acronyms

Acronym	Definition
cGMP	Current Good Manufacturing Practices
CMC	Calibration and Measurement Capabilities
DUT	Device Under Test
EMU	Expanded Measurement Uncertainty
MU	Measurement Uncertainty
NDI	Non-Destructive Inspection (NDI), also referred to as Non-Destructive Testing (NDT): A method of testing or evaluating materials and components without causing damage to the tested item.
NIST	National Institute of Standards and Technology, (US).
OOT	Out of Tolerance
SI Unit	The international system of units, comprised of 7 base units
SI Derived Unit	22 derived units of measure, derivatives of SI base units.
TAR	Test Accuracy Ratio
TUR	Test Uncertainty Ratio
QMS	Quality Management System
QSR	Quality System Regulation (FDA)
UUT	Unit Under Test

References

1. International vocabulary of metrology – Basic and general concepts and associated terms (VIM) 3rd edition, Retrieved from: https://www.bipm.org/documents/20126/2071204/JCGM_200_2012.pdf

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