In web design, a slider, also known as a carousel, is an interactive element that displays a series of images, text, or other content in a rotating fashion, usually horizontally. Sliders are commonly used on homepages to showcase featured products, services, promotions, or important information. They can be automated or controlled by the user, allowing for dynamic presentation of content. While sliders can be visually engaging, their use in web design should be balanced with usability and performance considerations, as they can affect page load times and user experience.