A quote currency is the second currency in a currency pair, which represents the currency that is being traded against the base currency. In forex trading, there are several commonly used quote currencies, including the US dollar (USD), the euro (EUR), the British pound (GBP), the Japanese yen (JPY), the Swiss franc (CHF), the Canadian dollar (CAD), and the Australian dollar (AUD).

The US dollar is the most widely used quote currency in forex trading, and is involved in the majority of currency pairs. The euro and the British pound are also commonly used as quote currencies, particularly in pairs involving currencies from European countries.

The Japanese yen is also widely used as a quote currency, particularly in pairs involving the US dollar. Meanwhile, the Swiss franc is often used as a quote currency in pairs involving the euro, and the Canadian dollar and Australian dollar are commonly used as quote currencies in pairs involving the US dollar.

Overall, the choice of quote currency will depend on the currency pair being traded and the market conditions at the time. Traders should be aware of the characteristics and potential risks associated with each quote currency, and use this information to inform their trading decisions.