the size of a ship or the amount it can carry, expressed in tons （表示船舶大小或载重量的）吨位◆a large amount of new tonnage—268 new ships this year alone 大量新增吨位 ── 仅今年就有 268 艘新船
the total amount that sth, especially cargo, weighs （货物等的）总重量◆Rail freight tonnage along the route has dropped 20% in the last year. 去年，本路线的铁路货运总重量下降了 20%。