The parent scope in Angular refers to the scope of the parent element of any page.

Now, in the above case, you can access the variables attached to the parentController using the childController through the parent scope.

In ANgular, all the applications have a $rootScope which is basically the scope created on an HTML element containing the ng-app directive.

BY Best Interview Question ON 20 Sep 2020

Example

For example, here you have an element which is nested within another element using its own controller:
 <div ng-controller="parentController">
  ... something in the parent element
  <div ng-controller="childController">
     ... something in the child element
  </div>
</div>