What do the position names “long” (LONG) and “short” (SHORT) mean?
In slang of traders “to open a long position” means to buy the base currency and “to open a short position” means to sell the base currency. For example, the trader has bought Euro 100,000 for Dollars, i.e. has opened a long position on euro. BUY 100,000 EUR/USD – a long position on euro. SELL 100,000 EUR/USD – a short position on euro.