XAML (eXtensible Application Markup Language) is a declarative programming language developed by Microsoft for designing user interfaces in Windows applications. It allows developers to define the layout, appearance, and behavior of visual elements such as buttons, menus, and settings screens in a clear, readable format. XAML separates the user interface design from the underlying application logic, making it easier to create and maintain interactive and visually appealing Windows apps. It is widely used in frameworks like Windows Presentation Foundation (WPF) and Universal Windows Platform (UWP).