noun pl. tons, ton

1. a unit of weight, equal to 2,000 pounds avoirdupois (907.1847 kilograms or 0.90718 metric ton or 0.8929 long ton), commonly used in the U.S., Canada, South Africa, etc.
   in full short ton
2. a unit of weight, equal to 2,240 pounds avoirdupois (1,016.0469 kilograms or 1.016 metric tons or 1.12 short tons), commonly used in Great Britain
   in full long ton
3. metric ton
4. a unit of internal capacity of ships, equal to 100 cubic feet (or 2.8317 cubic meters)
   in full register ton
5. a unit of carrying capacity of ships, usually equal to 40 cubic feet
   also called measurement ton or freight ton
6. a unit for measuring displacement of ships, equal to 35 cubic feet: it is approximately equal to the volume of a long ton of sea water
   in full displacement ton
7. ☆ a unit of cooling capacity of an air conditioner, equal to 12,000 Btu per hour
8. Informal a very large amount or number

Etymology: var. (differentiated (17th-c.) for senses “weight, measure”) of tun

noun

Etymology: Fr: see tone