system of units, based on a given system of quantities, in which the measurement unit for each derived quantity is a coherent derived unit
EXAMPLE Set of coherent SI units and relations between them.
NOTE 1 A system of units can be coherent only with respect to a system of quantities and the adopted base units.
NOTE 2 For a coherent system of units, numerical value equations have the same form, including numerical factors, as the corresponding quantity equations.