iOS UI refers to the user interface design of Apple's mobile operating system, iOS. It emphasizes simplicity, clarity, and ease of use, allowing users to navigate their devices intuitively. The design incorporates elements like touch gestures, icons, and widgets that enhance user interaction. Key features of iOS UI include a consistent layout across apps, vibrant colors, and smooth animations. The interface is designed to be responsive, adapting to different screen sizes and orientations. Additionally, iOS supports accessibility features, ensuring that all users, including those with disabilities, can effectively use their devices.