In English law, poundage was an ad valorem customs duty imposed on imports and exports at the rate of 1 shilling for every pound of goods imported or exported.[1]
The levy was introduced in 1347 and continued for many years at the same rate until after the Restoration from when Parliament set the rates according to current needs.[1]
Poundage was closely associated with tonnage, or tunnage, which was a duty on every tun of wine imported.[1]
In Britain the term poundage is used for the charge imposed on the sale of a postal order.[2]