The Roman ounce, equal to about 27.2875 grams or 0.9625 ounce avoirdupois. There were 12 ounces in a Roman pound, and the word uncia means a 12th part; its name gives us both the ounce and th inch
Russ Rowlett (Director), How Many? A Dictionary of Units of Measurement, Center for Mathematics and Science Education University of North Carolina, USA 2005. http://www.unc.edu/~rowlett/units/dictA.html, (Unit of Meas and Covr Factors - Amer) {608}