Dictionary · Standards & Units
System of units
A set of base and derived units, with their multiples and submultiples, defined under given rules for a given system of quantities.
Related terms
More from Standards & Units
Derived unit
A measurement unit for a derived quantity, formed as a product of powers of base units — the newton (kg·m·s⁻²) or the pascal (N/m²).
VIM (JCGM 200:2012) 1.11
International measurement standard
A standard recognized by signatories to an international agreement and intended to serve worldwide.
VIM (JCGM 200:2012) 5.2
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
Kind of quantity
The aspect common to mutually comparable quantities — length, mass, and energy are kinds; diameter and wavelength are both quantities of the kind length.
VIM (JCGM 200:2012) 1.2
Ordinal quantity
A quantity defined by an agreed procedure that can be ranked but has no meaningful algebra — Rockwell hardness or earthquake magnitude: order exists, differences and ratios do not.
VIM (JCGM 200:2012) 1.26
International System of Quantities (ISQ)
The system of quantities based on the seven base quantities: length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity — the quantity framework beneath the SI.
VIM (JCGM 200:2012) 1.6