The quotation of two different currencies, with the first listed currency (base) valued in units of the second (quote) currency. In forex trading, all trades involve swapping one currency for another; e.g. in EUR/USD, you are trading euros against US dollars. Major currency pairs are those that include the USD and a major currency (EUR, JPY, GBP, etc.), while minors and exotics are defined separately (see Exotic Currencies and Minor Currency).