World Trade Organization
The World Trade Organization (WTO) is an organization set up to supervise and liberalize international trade. It started work on 1 January 1995 under the Marrakech Agreement, replacing the General Agreement on Tariffs and Trade (GATT), which dated from 1948. It deals with regulation of trade between participating countries; it provides a framework for negotiating and formalizing trade agreements, and a dispute resolution process aimed at enforcing participants' adherence to WTO agreements which are signed by representatives of member governments  and ratified by their parliaments. Most of the issues that the WTO focuses on derive from previous trade negotiations, especially from the Uruguay Round (1986–1994).
The headquarters are at Geneva in Switzerland.
Further information: Wikipedia article
In relation to Singapore
Singapore has been a member of the World Trade Organization since 1995.