tonnage duty tonnage displacement • tonnage opening · · · Info · Definitions · Synonyms · Characters · · tonnage duty · · Text Common · · Latin · · Scripts 12 · · Length 4 · · Syllables Definitions · · · (noun) a tax imposed on ships that enter the US; based on the tonnage of the ship. Synonyms: tonnage, tunnage, tonnage duty. · · Noun Definition 1 Synonyms · · · tonnage · · Synonym 1 tunnage · · Synonym 2 Characters · · space U+0020 a latin small letter a U+0061 d latin small letter d U+0064 e latin small letter e U+0065 g latin small letter g U+0067 n latin small letter n U+006E o latin small letter o U+006F t latin small letter t U+0074 u latin small letter u U+0075 y latin small letter y U+0079