The General Agreement on Tariffs and Trade (GATT) is a multilateral agreement regulating international trade, the purpose of which is the "substantial reduction of tariffs and other trade barriers and the elimination of preferences, on a reciprocal and mutually advantageous basis".
Source: Boundless. “The General Agreement on Tariffs and Trade (GATT).” Boundless Business. Boundless, 21 Jul. 2015. Retrieved 06 Dec. 2015 from https://www.boundless.com/business/textbooks/boundless-business-textbook/international-business-4/international-trade-agreements-and-organizations-39/the-general-agreement-on-tariffs-and-trade-gatt-196-1789/