Dictionary · Standards & Units
Submultiple of a unit
A unit obtained by dividing a given unit by an integer greater than one — the millimetre from the metre.
Related terms
More from Standards & Units
Derived quantity
A quantity in a system of quantities defined in terms of the base quantities of that system — speed, force, pressure.
VIM (JCGM 200:2012) 1.5
Base unit
A measurement unit adopted by convention for a base quantity — in the SI: second, metre, kilogram, ampere, kelvin, mole, candela.
VIM (JCGM 200:2012) 1.10
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
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
Measurement unit
A real scalar quantity, defined and adopted by convention, with which any other quantity of the same kind is compared to express the ratio of the two quantities as a number.
VIM (JCGM 200:2012) 1.9
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