Tariff
A tariff is a tax on imports or exports between sovereign states. It is a form of regulation of foreign trade. It is a policy that taxes foreign products to encourage or protect domestic industry. It helps limit trade deficits. The tariff is historically used to protect infant industries and to allow import substitution industrialization.
McKinley Tariff
Tariffs, taxes on foreign goods entering a country, served two purposes for the United States in the late 19th century. One was to raise revenue for the federal government, and the other was to protect domestic manufacturers from foreign competition, which is known as protectionism.