The world's largest developer and published of international standards. The ISO is a network of the national standards institutes of 163 countries, coordinated by a Central Secretariat in Geneva. 
For example, in a currency context, ISO 4217 is the international standard established by the ISO that specifies the structure for the three-letter codes used to describe the many currencies used around the world. 

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The ISO 4217 Code for a currency generally consists of the country's two-character country code (ISO 3166-1 alpha-2) plus an additional character referring to its currency unit. For example, the U.S. dollar is represented by USD, the Japanese yen by JPY, and so on.