A traditional unit of liquid volume, generally equal to the wine (or U.S. liquid) gallon (about 3.785 liters). A flagon is a large, narrow-necked pitcher or bottle
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}