customs union

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An international association organized to eliminate customs restrictions on goods exchanged between member nations and to establish a uniform tariff policy toward nonmember nations.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun a type of trade bloc which is composed of a free trade area with a common external tariff

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an association of nations to promote free trade within the union and set common tariffs for nations that are not members