The "Keyup" event occurs in computer programming when a user releases a key on their keyboard. This event is commonly used in web development to trigger specific actions, such as submitting a form or updating content on a webpage. It is part of the broader category of keyboard events, which also includes "Keydown" and "Keypress." In JavaScript, the "Keyup" event can be detected using event listeners. When a key is released, the event listener executes a function that can respond to the action. This allows developers to create interactive applications that respond to user input in real-time, enhancing the overall user experience.