Is flutter a programming Language ?

Flutter

No, Flutter is a Framework not a programming language , developed by Google.

In simple language , Flutter create structure for you, now its up to you where you use this structure mean for Android app develoment, iOS development, Window app, Linux App, Web app etc

So when you install flutter framework first you create flutter app

flutter create anyPlatformApplication

Now, after creating a Flutter app i.e. AnyPlatformApplication, Flutter creates the basic template for you and now you can write the code and develop any type of application (mobile, web, desktop) through Dart programming.

The best thing of flutter framework is you can build any application no major changes require with simple commands

flutter build apk //Android app

or

flutter build web //Web app

or 

flutter build ios //ios app

In this way you can build any platform based application in flutter “Write Once run anywhere”