/tun"ij/ , n.
1. the capacity of a merchant vessel, expressed either in units of weight, as deadweight tons, or of volume, as gross tons.
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.
Also, tunnage .
[ 1375-1425; late ME: duty 1 , -AGE ]