FOREX — the foreign exchange market or currency market or Forex is the market where one currency is traded for another. It is one of the largest markets in the world.
Some of the participants in this market are simply seeking to exchange a foreign currency for their own, like multinational corporations which must pay wages and other expenses in different nations than they sell products in. However, a large part of the market is made up of currency traders, who speculate on movements in exchange rates, much like others would speculate on movements of stock prices. Currency traders try to take advantage of even small fluctuations in exchange rates.
In the foreign exchange market there is little or no 'inside information'. Exchange rate fluctuations are usually caused by actual monetary flows as well as anticipations on global macroeconomic conditions. Significant news is released publicly so, at least in theory, everyone in the world receives the same news at the same time.
Currencies are traded against one another. Each pair of currencies thus constitutes an individual product and is traditionally noted XXX/YYY, where YYY is the ISO 4217 international three-letter code of the currency into which the price of one unit of XXX currency is expressed. For instance, EUR/USD is the price of the euro expressed in US dollars, as in 1 euro = 1.2045 dollar.