ISO 4217

ISO 4217 is the international standard describing three-letter codes (also known as the currency code) to define the names of currencies established by the International Organization for Standardization (ISO). The ISO 4217 code list is the established norm in banking and business all over the world for defining different currencies, and in many countries the codes for the more common currencies are so well known publicly, that exchange rates published in newspapers or posted in banks use only these to define the different currencies, instead of translated currency names or ambiguous currency symbols. ISO 4217 codes are used on airline tickets and international train tickets to remove any ambiguity about the price. The first two letters of the code are the two letters of ISO 3166-1 alpha-2 country codes (which are also used as the basis for national top-level domains on the Internet) and the third is usually the initial of the currency itself. So Japan's currency code becomes JPY—JP for Japan and Y for yen.