What is traded in the forex market?

The foreign exchange market is an international decentralized market for the trading of
currencies. Most people are unaware that this market is 10 times larger than any stock market,
operates a daily trade volume of over $4 trillion and presents endless opportunities for individual
traders. Traders profit from the differences of currency price rates.

Forex transactions are quoted in pairs since you are buying one currency while selling another.
The first currency is the base currency and the second currency is the quote currency.