The `pointerup` event is part of the Pointer Events API, which allows developers to handle input from various devices like a mouse, touch screens, and styluses. This event is triggered when a pointer (such as a finger or mouse cursor) is released after being pressed down on a target element. It is useful for detecting when a user has finished an interaction, such as clicking a button or lifting a finger from a touchscreen. When the `pointerup` event occurs, it provides information about the pointer, including its position and the type of device used. This event can be used in conjunction with other pointer events, like `pointerdown` and `pointermove`, to create more interactive and responsive web applications.