Final answer:
The term that describes a coalition of countries with agreements on trade of goods among themselves and a common external trade policy is a Customs Union.
Step-by-step explanation:
The term that describes a group of countries that agree on a set of special arrangements governing the trading of goods between member countries is a Customs Union. A Customs Union involves countries agreeing on trade policies among themselves and adopting a common external trade policy. On the other hand, a Free Trade Agreement allows countries to have free trade between each other but lets them control their own policies towards non-members. A common market is a step beyond a customs union, allowing for the free movement of goods, services, labor, and capital in addition to a common trade policy. An Economic Union is a type of common market that also requires coordinated fiscal and monetary policies. A tariff is a tax imposed on imports, and an import quota is a limit on the quantity of a good that can be imported.