Derived quantities are products and ratios of the fundamental quantities that exist in a system of units.  For example, the seven fundamental quantities of the SI system of units are length, mass, time, electric current, temperature, amount of substance, and luminous intensity.  The corresponding units are meter, kilogram, second, Ampere, Kelvin, mole, and candela.  One derived quantity is the meter per second, which are units of velocity and is a simple ratio: m/s.  A more complex derived quantity is energy, with units of m2Kg/s2 . There are many more derived quantities, but all are products and/or ratios of the seven fundamental quantities.