Note: Goods from Canada and Mexico that fall under the U.S.M.C.A. trade pact — the agreement that replaced NAFTA — are not subject to tariffs that took effect in March targeting those countries.

Put simply, a tariff is a tax on the cost of importing or exporting goods by a particular country. So, for example, a "60% tariff" on Chinese imports would be a 60% tax on the price of importing ...