Definition of tonnage

• n. - The weight of goods carried in a boat or a ship.
• n. - The cubical content or burden of a vessel, or vessels, in tons; or, the amount of weight which one or several vessels may carry. See Ton, n. (b).
• n. - A duty or impost on vessels, estimated per ton, or, a duty, toll, or rate payable on goods per ton transported on canals.
• n. - The whole amount of shipping estimated by tons; as, the tonnage of the United States. See Ton.