Ton — a unit of weight, commonly the metric ton (1,000 kilograms); usually written in katakana.
このトラックは最大積載量が3トンです。
This truck has a maximum load capacity of 3 tons.
鋼材を10トン輸送する予定だ。
We plan to transport 10 tons of steel.
輸送費は荷物の重さ（トン）で計算されます。
Shipping costs are calculated based on the weight (tons) of the cargo.