A traditional unit in Spanish and Portuguese speaking countries. The word means "load". It was often used as a unit of mass or weight equal to 3 quintals or as a unit of volume equal to the volume holding 3 quintals of the commodity being shipped
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}