An “One Cancels the Other Order” (OCO) is a type of order used in trading. It involves placing two orders simultaneously, where the execution of one order automatically cancels the other.
For example, a trader may place a buy limit order for a currency pair at a certain price level, along with a sell stop order for the same currency pair at a lower price level. If the buy limit order gets executed, the sell stop order will automatically get canceled, and vice versa. This type of order is typically used by traders who want to limit their losses and protect their profits at the same time, by setting up both a stop-loss and a take-profit order in one go.