tonnage

American  

[tuhn-ij] / ˈtʌn ɪdʒ /

Or tunnage

noun

1. the capacity of a merchant vessel, expressed either in units of weight, as deadweight tons, ton, or of volume, as gross tons. ton.

2. ships collectively considered with reference to their carrying capacity or together with their cargoes.

3. a duty on ships or boats at so much per ton of cargo or freight, or according to the capacity in tons. ton.

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tonnage British  

/ ˈtʌnɪdʒ /

noun

1. the capacity of a merchant ship expressed in tons, for which purpose a ton is considered as 40 cubic feet of freight or 100 cubic feet of bulk cargo, unless such an amount would weigh more than 2000 pounds in which case the actual weight is used

2. the weight of the cargo of a merchant ship

3. the total amount of shipping of a port or nation, estimated by the capacity of its ships

4. a duty on ships based either on their capacity or their register tonnage

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Etymology

Origin of tonnage

1375–1425; late Middle English: duty < Old French. See ton ¹, -age

Explanation

Tonnage is a type of tax. Tonnage is charged to the owners of ships that enter the United States, and the charge depends on how much their freight weighs. See the word ton in tonnage? That’s a clue this word is related to weight. In fact, it has to do with how much cargo weight is on a ship that's entering the U.S. The greater the weight, the greater the tonnage, which is a tax the ship’s owners must pay. Companies that ship a lot of heavy, bulky goods to the U.S. have to pay a lot of tonnage.

Example Sentences

Over this period, the Indian navy more than doubled its tonnage, but China’s naval tonnage more than quadrupled.

From The Wall Street Journal • Feb. 25, 2026

“These are still small steps in tonnage, but giant strides in independence,” Innes observed.

From MarketWatch • Oct. 17, 2025

Vessel owners are often lax about tonnage or safety standards.

From Barron's • Oct. 13, 2025

While China has the world's largest navy by number of vessels, the US fleet has a greater overall tonnage and is more powerful - with far more large aircraft carriers.

From BBC • Aug. 31, 2025

Splashing cold water on his face, the tonnage of missed sleep stacked on his brain lightened only slightly.

From "The Great Santini" by Pat Conroy

Related Words

• amount
• breadth
• capacity
• content
• diameter
• extent
• height
• intensity
• length
• magnitude
• proportion
• range
• scope
• stature
• volume
• width