Chapter Tolerate to Ton of T by Webster's Dictionary (1913 Edition)

In England, the ton is 2,240 pounds. In the United States the ton is commonly estimated at 2,000 pounds, this being sometimes called the short ton, while that of 2,240 pounds is called the long ton.

(b) (Naut. & Com.) Forty cubic feet of space, being the unit of measurement of the burden, or carrying capacity, of a vessel; as a vessel of 300 tons burden. See the Note under Tonnage.

(c) (Naut. & Com.) A certain weight or quantity of merchandise, with reference to transportation as freight; as, six hundred weight of ship bread in casks, seven hundred weight in bags, eight hundred weight in bulk; ten bushels of potatoes; eight sacks, or ten barrels, of flour; forty cubic feet of rough, or fifty cubic feet of hewn, timber, etc.

Ton and tun have the same etymology, and were formerly used interchangeably; but now ton generally designates the weight, and tun the cask. See Tun.