OCO order
OCO (One Cancels the Other) is a pair of linked orders. When one fills, the other is cancelled automatically.
A common use is the exit from a position: a take-profit and a stop-loss at once. OCO also fits when you expect a sharp move but not its direction: one order to buy, the other to sell.
Example
You bought at 100. You set an OCO: a limit sell at 110 and a stop at 95. Price reached 110, the order filled, and the stop vanished on its own. Nothing to cancel by hand.
What not to do
Do not assume OCO guarantees the price: the stop leg can fill worse because of slippage. And first check that your platform supports OCO at all.
WEEX
FxPro
Vantage