Forex (FX) refers to the global electronic marketplace for trading international currencies and currency derivatives. It has no central physical location, yet the forex market is the largest, most liquid market in the world by trading volume, with trillions of dollars changing hands every day. Most of the trading is done through banks, brokers, and financial institutions.
The forex market is open 24 hours a day, five days a week, except for holidays. The forex market is open on many holidays on which stock markets are closed, though the trading volume may be lower.
Its name, forex, is a portmanteau of foreign and exchange. It's often abbreviated as fx.