If we consider an AngularJS application to consist of: View, which is the HTML. Model, which is the data available for the current view. Controller, which is the JavaScript function that makes/changes/removes/controls the data. Then the scope is the Model. The scope is a JavaScript object with properties and methods, which are available for both the view and the controller.
The property "carname" was made in the controller, and can be referred to in the view by using the {{ }} brackets.