A "tariff" is the general term for the tax that a government levies on products imported from other countries. Sometimes the words "duty," "customers," "customs duty" and "imported duties" are also used to convey the same meaning.
In international trade, governments make this tax obligatory for different reasons, one of which is to raise revenue. However, not every item is taxed. Most countries maintain a "free list" of goods that are not subject to a tariff.
Other taxes may be applied to imported goods, depending on the country and the commodity. For example, the U.S. charges a federal excise tax on imported alcoholic beverages and tobacco products.