Foreign exchange; also the global market where different fiat currencies are exchanged.
Forex, short for foreign exchange, is the global market where fiat currencies are exchanged based on agreed-upon exchange rates. The market is characterized by traders, investors, and financial institutions who trade in currency pairs, thereby making profit from the difference in value. The entire market is based on changes in currency values, and can be described as the origin of the arbitrage strategy of trading.
The forex market has a significant influence in the currency exchange market, thereby determining exchange rates most of the time. As a result, it is the biggest financial market in the world in terms of daily trading volumes.