A currency pair is a quotation of two different currencies in the foreign exchange market, where the value of one currency (the base currency) is expressed in terms of the other (the quote currency). Currency pairs are categorized as major pairs (involving the US dollar), minor or cross pairs (without the US dollar), and exotic pairs (pairing a major currency with one from a developing economy). The first listed currency is always the base currency, and the second is the quote currency.
Example
“When EUR/USD is quoted at 1.1050, it means one euro can be exchanged for 1.1050 US dollars. A trader who buys this pair profits if the euro strengthens relative to the dollar.”