Another name for barrier option. By definition, it is an exotic option whose payoff depends on whether the underlying asset price reaches a specified threshold or limit (a predetermined knock-in or knock-out price) or not. A knock-in option comes into existence only when the underlying asset reaches the threshold (the barrier). To the contrary, knock-out options cease to exist if the asset price reaches or breaches the barrier.
This option is alternatively known as a stoption.
