Knowledge
Metrology Dictionary
The complete VIM vocabulary — all numbered concepts of JCGM 200:2012 as faithful paraphrases with clause citations — plus clearly labeled practice terms from the GUM, ILAC, ISO and NIST guidance.
Quantity
A property of a phenomenon, body, or substance to which a magnitude can be assigned and expressed as a number and a reference (typically a measurement unit).
VIM (JCGM 200:2012) 1.1 · Standards & Units
Quantity calculus
The set of mathematical rules applied to quantities rather than bare numbers — the algebra by which units propagate through equations.
VIM (JCGM 200:2012) 1.21 · Standards & Units
Quantity dimension
The expression of a quantity's dependence on the base quantities as a product of powers of their dimensions — force has dimension L·M·T⁻².
VIM (JCGM 200:2012) 1.7 · Standards & Units
Quantity equation
A mathematical relation between quantities in a system of quantities, independent of units — v = l/t regardless of whether metres or inches are used.
VIM (JCGM 200:2012) 1.22 · Standards & Units
Quantity of dimension one
A quantity whose dimension has all base-quantity exponents equal to zero — refractive index, strain, a ratio of like quantities; often loosely called "dimensionless".
VIM (JCGM 200:2012) 1.8 · Standards & Units
Quantity value
A number together with a reference (such as a measurement unit) expressing the magnitude of a quantity — 5.34 m, 0.152 kg, or a value on an agreed scale.
VIM (JCGM 200:2012) 1.19 · Standards & Units
Quantity-value scale
The ordered set of values that quantities of a given kind may take — the scale a thermometer or hardness tester reports on.
VIM (JCGM 200:2012) 1.27 · Standards & Units