iso 4217 is the international standard describing three-letter codes (also known as the currency code) to define the names of currencies, as established by the international organization for standardization (iso). the iso 4217 code list is the common way in banking and business, all over the world, for defining different currencies. in many countries, the codes for the more common currencies are so well-known, by the general public, that exchange rates written in newspapers or posted in banks use only those codes to define the different currencies, instead of translated currency names or currency symbols. iso 4217 codes are used on airline tickets and international train tickets to remove any uncertainty about the price.