Long

To "go long" means to buy an asset with the expectation that its price will rise. In forex, going long EUR/USD means you're buying euros and selling dollars. If EUR/USD rises, you profit. If it falls, you lose. The word "long" comes from old Wall Street slang — you hold an asset "for the long term" hoping it appreciates. It doesn't actually imply time duration; you can be long for 10 seconds or 10 years, either way you still "went long." Opposite of long is short (selling something you don't own, profiting if it falls). In forex, longs and shorts are equally easy — you don't need to borrow anything to go short a currency pair because every forex trade is already a simultaneous buy and sell.