Definition:Roman Weights and Measures/Mass/Uncia/Historical Note

Historical Note on Uncia
The uncia continued to be used as a unit of mass in Europe after the fall of Rome, evolving into the ounce.

It is understood to be of the same mass as the apothecaries' ounce and troy ounce, and is about $10 \%$ heavier than the ounce avoirdupois.