0.02 International System of Units

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system of units, based on the International System of Quantities, their names and symbols, including a series of prefixes and their names and symbols, together with rules for their use, adopted by the General Conference on Weights and Measures (CGPM)1


[OIML V2-200:2012, 1.16]

Note 1 The SI is founded on the seven base quantities and a set of seven defining constants. See: OIML V 2-200:2012, 1.16 and the SI Brochure published by the Bureau International des Poids et Mesures (BIPM) and available on the BIPM website [BIPM 2019 ].

Note 2 The base units and the coherent derived units of the SI form a coherent set, designated the “set of coherent SI units”.

Note 3 For a full description and explanation of the International System of Units, see the current edition of the SI Brochure [BIPM 2019].

Note 4 In quantity calculus, the quantity 'number of entities' is often considered to be a base quantity, with the base unit one, symbol 1.

Note 5 The SI prefixes for multiples of units and submultiples of units are given in OIML V2-200:2012, 1.16.

1The definition of the SI is a quote from OIML V 2-200:2012. OIML V 2-200:2012 is currently under revision; this may result in a new definition of the SI. In 2019, there was a redefinition of the SI where all units, especially base units, are expressed in terms of defining constants.

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