Forex and FX are interchangeable abbreviations for Foreign Exchange, which is a term used to refer to the global currency markets.
Forex is hands down the largest market in the world. The Bank of International Settlements’ (BIS) report of April 2013 has foreign exchange turnover at a record-breaking 5.4 trillion US dollars per day. This figure dwarfs the daily turnover of all the world’s equity markets combined.
Unlike stocks, bonds and options, Forex markets are open around the clock between Monday and Friday. As a result you do not have to wait for markets to open, they are always open, leaving you free to trade whenever you like. The sun never sets on forex traders.