WinRT/Metro application development refers to creating modern, touch-friendly apps for Windows platforms using the Windows Runtime (WinRT) framework. This approach enables developers to build responsive and visually appealing applications that work seamlessly across various Windows devices, including tablets, PCs, and smartphones. WinRT apps utilize a design language formerly known as "Metro," which emphasizes clean, minimalist interfaces and fluid animations. By leveraging WinRT, developers can access a rich set of APIs and tools to create powerful, native Windows applications that integrate well with the operating system's features and provide a consistent user experience.