First of all, you have to realize that the understanding of these terms is relative to what is being discussed. Generally speaking, when you go long a currency it means you bought it and are holding it in the expectation that it will appreciate in value. By contrast, going short means you re selling currency in the expectation that what you re selling will depreciate in value. Specifically, if you re going long Sterling, it means you are buying or holding onto Sterling. At the same time, when you buy Sterling it means you re shorting the dollar.
Volatility is the average movement in any given period of time.
The higher the average, the higher the volatility. This is the level that you can place to protect your position from unexpected losses. The intention of the Global Forex dealer is to keep your position open until the time is absolutely necessary to liquidate it so as to protect you from further losses. Your closing price might vary slightly from the stop-loss position you requested due to volatility. As a new trader you ll discover that learning to place a sensible stop-loss position becomes somewhat of an art.