Let’s try to define what is an application framework, for that we will check how famous website defines the term “Application Framework”

From Wikipedia 

In computer programming, an application framework[1] consists of a software framework used by software developers to implement the standard structure of application software.[2]

From techopedia

An application framework is a software library that provides a fundamental structure to support the development of applications for a specific environment. An application framework acts as the skeletal support to build an application.

Now my own definition of an application framework

An application framework is a set of tools, components and design patterns that allow the programmer to develop an application for a well define pourpose (like a business application, a game etc..). The main pourpse of an application framework should be reduce the development time and allow the developer to focus on the main pourpouse of the application instead of the application infrastructure

That is all for now, as you can see the concept is really simple but as they say “devil lies on the details”. In the upcoming post, we will define the parts of an application framework.