1. General definitions
1.1 Size and unity
A magnitude is an attribute of a phenomenon, body or substance that can be distinguished qualitatively and determined quantitatively. The term magnitude can refer to a quantity in a general sense, e.g. length, time, mass, electrical resistance, etc., or to a particular quantity, e.g. the length of a given rod, the electrical resistance of a given sample of wire. Quantities that can be ranked in relation to each other in ascending (or descending) order are called quantities of the same kind.
The unit of measurement is a particular quantity, defined and adopted by convention, to which other quantities of the same kind are compared in order to express them quantitatively in relation to this quantity.
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General definitions
Responsible organizations
Bibliography
Standardization
The Association française de normalisation (AFNOR) provides readers with collections of French, foreign and international standards, which can also be purchased from AFNOR. In each country, the national standards body can provide the same services.
France
French Standards Association (AFNOR)
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Websites
Main organizations responsible
International Organization of Metrology OIML http://www.oiml.org/
International Organization for Standardization ISO http://www.iso.org/
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