In finance, an exchange rate (also known as a foreign-exchange rate, forex rate, FX rate or Agio) between two currencies is the rate at which one currency will be exchanged for another. It is also regarded as the value of one country’s currency in terms of another currency. For example, an interbank exchange rate of 119 Japanese yen (JPY, ¥) to the United States dollar (US$) means that ¥119 will be exchanged for each US$1 or that US$1 will be exchanged for each ¥119. In this case it is said that the price of a dollar in terms of yen is ¥119, or equivalently that the price of a yen in terms of dollars is $1/119.
Exchange rates are determined in the foreign exchange market, which is open to a wide range of different types of buyers and sellers where currency trading is continuous: 24 hours a day except weekends, i.e. trading from 20:15 GMT on Sunday until 22:00 GMT Friday. The spot exchange rate refers to the current exchange rate. The forward exchange rate refers to an exchange rate that is quoted and traded today but for delivery and payment on a specific future date.
In the 17th and 18th century, the use of silver Spanish dollars or "pieces of eight" spread from the Spanish territories in the Americas westwards to Asia and eastwards to Europe forming the first worldwide currency. Spain's political supremacy on the world stage, the importance of Spanish commercial routes across the Atlantic and the Pacific, and the coin's quality and purity of silver helped it become internationally accepted for over two centuries. It was legal tender in Spain's Pacific territories of the Philippines, Micronesia, Guam and the Caroline Islands and later in China and other Southeast Asian countries until the mid-19th century. In the Americas it was legal tender in all of South and Central America (except Brazil) as well as in the US and Canada until the mid-19th century. In Europe the Spanish dollar was legal tender in the Iberian Peninsula, in most of Italy including: Milan, the Kingdom of Naples, Sicily, Sardinia, the Franche-Comté (France), and in the Spanish Netherlands. It was also used in other European states including the Austrian Habsburg territories.