derived unit that, for a given system of quantities and for a chosen set of base units, is a product of powers of base units with no other proportionality factor than one

EXAMPLES: If the metre, the second, and the mole are base units, the metre per second is the coherent derived unit of velocity when velocity is defined by the quantity equation v = dr/dt, and the mole per cubic metre is the coherent derived unit of amount-of-substance concentration when amount-of substance concentration is defined by the quantity equation c = n/V. The kilometre per hour and the knot, given as examples of derived units in 1.11, are
not coherent derived units in such a system of quantities. The centimetre per second is the coherent derived unit of speed in a CGS system of units but is not a coherent derived unit in the SI.