Forex (Foreign Exchange or FX) is the trading of currencies that taken place in a global decentralized or over-the-counter market. Through a broker or dealer, traders can buy or sell currencies in pairs simultaneously, like USD/JPY, which sets the US dollar against the Japanese Yen.
The Foreign Exchange market is the largest, most liquid market in the world with 24 hours continuous operation, huge trading volume and the participation of larger international banks, brokers, institutions, and individual traders.