A currency pair is a foreign exchange exchange rate composed of two currencies, represented by two ISO codes plus a separator, such as GBP/USD, where the first code represents the “primary currency” and the other is the “secondary currency”.
The mainstream currency pairs in the foreign exchange market are mainly currency pairs containing the U.S. dollar, such as the euro/dollar (EUR/USD), British pound/dollar (GBP/USD), Australian dollar/dollar (AUD/USD) and so on.
The most commonly traded currencies in the most common currency markets are called “major currencies”. Most currencies are bought and sold against the U.S. dollar (USD). The US dollar (USD) is the most traded currency.
The next five most frequently traded currencies are: Euro (EUR); Japanese Yen (JPY); British Pound (GBP); Swiss Franc (CHF) and Australian Dollar (AUD). The transactions of these six major currencies account for 90% of the global foreign exchange market.