ton (tÅ­n) n. 1. A unit of weight equal to 2,000 pounds (0.907 metric ton or 907.18 kilograms). Also called net ton, short ton. 2. A unit of weight equal to 2,240 pounds (1.016 metric tons or 1,016.05 kilograms). Also called long ton. 3. A metric ton. See Table at measurement. 4. A unit of capacity for cargo in maritime shipping, normally estimated at 40 cubic feet. 5.