The most common way to protect one’s economy from import competition is to implement a tariff: a tax on imports. Generally speaking, a tariff is any tax or fee collected by a government. Sometimes the term “tariff” is used in a nontrade context, as in railroad tariffs. However, the term is much more commonly used to refer to a tax on imported goods. Read more 

Source:Policy and Theory of International Trade from http://2012books.lardbucket.org