Fluid layout is a web design approach that allows a website's elements to resize and adapt based on the user's screen size. This means that instead of fixed widths, elements are often defined in percentages, making them flexible and responsive. This adaptability enhances user experience across various devices, from desktops to smartphones. By using fluid layouts, designers can ensure that content remains accessible and visually appealing, regardless of the display size. This technique is particularly important in today's digital landscape, where users access websites on a wide range of devices, including tablets and smartphones.