displacement ton

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A unit for measuring the displacement of a ship afloat, equivalent to one long ton or about one cubic meter of salt water.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun nautical A unit approximately equal to the volume of a long ton weight of seawater, used in reckoning the displacement of ships, and equal to 35 U.S. or Imperial cubic feet.