In web design, what is meant by the term 'responsive design'?

Responsive design refers to a layout that adapts to different screen sizes, ensuring that users have a good viewing experience on a variety of devices, such as smartphones, tablets, laptops, and desktops. It involves using flexible grids, images, and CSS media queries to adjust the layout and content as the screen size changes. This approach is essential in modern web design because it provides accessibility and usability across multiple devices, enhances user experience, and helps in maintaining a consistent look and feel of the website regardless of how it's accessed.

The other options represent concepts that do not encompass the essence of responsive design. For instance, a design that only works on desktop browsers is restrictive and fails to cater to mobile users. A fixed-width web page does not adjust to different screen sizes, which can lead to poor user experience on devices that require a more flexible approach. Lastly, while focusing on loading speed is important for web design, it does not directly relate to the adaptability of layout in response to screen sizes.