Definition:Apothecaries' Weights and Measures/Mass/Pound/Historical Note

Historical Note on Apothecaries' Pound
The apothecaries' pound derived from the libra (Roman pound).

It is seen that an apothecaries' pound and a troy pound have the same mass.

Some sources do not recognise the existence of the apothecaries' ounce separately from the troy ounce, and when tabulating the various conversion factors refer merely to troy ounces and troy pounds.