A long position in forex refers to the purchase of a currency pair, anticipating that the base currency (the first listed currency) will appreciate in value relative to the quote currency (the second listed currency). Traders take a long position when they believe that the price of the currency pair will rise, allowing them to sell it later at a profit. For example, if a trader goes long on the EUR/USD pair, they expect the euro to increase in value against the US dollar, and they will profit if the euro appreciates after their purchase.