A tariff is a tax or custom duty on an imported [[good]]. It can take one of two forms: (1) a [[taxation|tax]] per unit, known as a specific tariff, or (2) a tax based on the value of the good, known as an ''ad valorem'' tariff. | A tariff is a tax or custom duty on an imported [[good]]. It can take one of two forms: (1) a [[taxation|tax]] per unit, known as a specific tariff, or (2) a tax based on the value of the good, known as an ''ad valorem'' tariff. |