Revenue Ton 3 or Tonne (RT) : A unit used for billing in the shipping industry. The size of a shipment in revenue tons is the number of metric tons or the number of cubic meters in the shipment, whichever is larger
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}