Mobile first refers to the design and development approach that prioritizes the mobile user experience over other devices. This means that when creating a website, app, or any digital product, the design and functionality are first optimized for mobile devices, such as smartphones and tablets, before being adapted for desktop or other devices. This approach recognizes the increasing use of mobile devices for accessing the internet and aims to provide a seamless and user-friendly experience for mobile users. By putting mobile first, designers and developers ensure that their product is accessible, efficient, and visually appealing on smaller screens, ultimately enhancing the overall user experience.