Tonnage

n. total capacity of a ship (calculated in tons); weight of cargo carried in a ship (calculated in tons); tax imposed on a ship's cargo; size of a fleet of ships (measured by the combined capacity of all ships)

Tonnage is a measure of the size or cargo capacity of a ship. The term derives from the taxation paid on tuns of wine, and was later used in reference to the weight of a ship's cargo; however, in modern maritime usage, "tonnage" specifically refers to a calculation of the volume or cargo volume of a ship. The term is still sometimes incorrectly used to refer to the weight of a loaded or empty vessel.
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Noun
1. a tax imposed on ships that enter the US; based on the tonnage of the ship
(synonym) tunnage, tonnage duty
(hypernym) duty, tariff

n. tonnage, total capacity of a ship, weight of cargo carried in a ship; tax imposed on a ship's cargo; size of a fleet of ship

n. tonnage, burden