Accreditation Authorisation, approval or recognition of meeting a standard.
Calibration A set of operations that establish, under specified conditions, the relationship between values of quantities indicated by a measuring system, or values represented by a material measure or a reference material, and the corresponding values realised by standards.
Conformity Fulfilment by a product, process or service of specified requirements.
Conformity assessment An activity concerned with determining directly or indirectly that relevant requirements are fulfilled.
International standard Standard recognised by an international agreement to serve internationally as the basis for assigning values to other standards of the quantity concerned.
International System of Units (SI) The units of the metric system used universally in science.
Legal metrology Legal metrology comprises all measurements carried out for any legal purpose and includes measurements that are subject to regulation by law or government decree.
Measurement A set of operations having the object of determining a value of a quantity.
Metre Convention The Metre Convention is an international treaty that provides the basis of all international agreements on units of measurement.
Metrology The science of measurement.
National 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.
Pattern approval Examination of the pattern (design) of a measuring instrument against national or international specifications.
Primary standard A 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.
Reference material A material or substance one or more of whose property values are sufficiently homogeneous and well established to be used for the calibration of an apparatus, the assessment of a measurement method, or for assigning values to materials.
Reference standard A standard generally having the highest metrological quality available at a given location or in a given organisation from which measurements made there are derived.
Secondary standard A standard whose value is assigned by comparison with a primary standard of the same quantity.
Traceability Traceability is the 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.
Working standard A standard that is used routinely to calibrate or check material measures, measuring instruments or reference materials.