A tariff is a tax that a government charges on goods brought in from other countries. When a company in Japan wants to sell cars in the United States, the U.S. government might add a tariff to those cars, making them more expensive for Americans to buy.

Governments use tariffs for different reasons. Sometimes they want to protect their own country's businesses: if American car companies face competition from cheaper foreign cars, a tariff on imported cars makes the foreign cars cost more, giving local companies a better chance to compete. Other times governments use tariffs to raise money, since every imported item that gets taxed brings revenue into the government's treasury.

Tariffs have shaped history in major ways. American colonists despised British tariffs on tea and other goods, which helped spark the Revolutionary War. In the 1800s, arguments over tariffs divided Northern and Southern states, since the industrial North wanted tariffs to protect their factories while the agricultural South wanted cheaper foreign goods.

The word can also mean a list of prices or fees for services. A hotel might post its tariff showing what each type of room costs, or a taxi company might display its tariff of fares for different distances.