Stop Loss is a type of risk management tool. It can prevent additional losses if the price goes against your position.
You went long (buy) EUR/USD at 1.12830. To limit your maximum loss, you set a stop-loss order at 1.12330. This means if you were wrong and EUR/USD drops to 1.12330 instead of moving up, your trading platform would automatically execute a sell order at 1.12330 the best available price and close out your position for a 50-pip loss