SDK means Software Development Kit
An SDK is sometimes referred to as a devkit and is a set of development tools for a particular platform, or application. With this SDK, a developer can work to build applications for the aforementioned platform. Known SDKs are the JAVA SDK, IOS SDK, Android SDK, etc. Usually, an SdK has a graphical tool, an editor a compiler and documentation and guidelines. With the included examples it is often easy to start quickly, there is the necessary programming knowledge needed to be able to write real applications.