“Open a long position” or “take a long position” means buy the base currency, and vice versa, “short position” means sell the base currency. Here is an example, a transaction for the purchase of 100 000 EURUSD means purchase of 100 000 euros for dollars. Thus, there is the opening of a long position in the euro. BUY (buy) 100 000 EURUSD – a long position on the Euro. SELL (sell) 100 000 EURUSD – a short position on the Euro.