An application platform refers to a software framework that provides the necessary tools and services for developers to build, deploy, and manage applications. It typically includes a runtime environment, development tools, and APIs for integrating with other systems. The platform provides a consistent and secure environment for developers to create applications, making it easier and faster to develop, test, and deploy them. It also allows for the reuse of code and components, reducing development costs and time. Some popular application platforms include Android, iOS, and Windows.