What does "chrome" mean in Android Navigation?

If you look at the Android navigation documentation, the word chorme appears frequently.

I would like to know exactly what it means.

NavHostFragment

NavHostFragment is intended to be used as the content area within a layout resource defining your app's chrome around it.

NavigationUI

Class which hooks up elements typically in the chrome of your application such as global navigation patterns like a navigation drawer or bottom nav bar with your NavController.

Maybe duplicate of this question. But I want to clarify the definition of chrome in Android.