Avoid confusion and call them:
- status bar
- app bar (action bar is also ok)
- navigation bar
Synonyms
action bar, app bar, and title bar all refer to the same thing. A Toolbar is a certain implementation of this bar.
One of the purposes of the status bar is to show notifications. Therefor some call it the notification bar.
The navigation bar is sometimes called the system bar, but the latter name should be avoided. It's too easy to mistakenly think that the system bar contains system information like battery level and network connection, while that's actually the job of the status bar to show these things. The term navigation bar is much clearer. I've also seen it getting called home bar.
Note that iOS also has a navigation bar where it serves a slightly different purpose compared to android - the purpose overlaps with android's navigation and action bars. Moreover, the navigation bar in iOS is typically (always?) located at the top, just below the status bar. See Navigation Bars on developer.apple.com.
References
- Android bars at material.io (status bar, app bar, navigation bar)
- Add the app bar at developer.android.com (app bar, action bar, Toolbar)
@android:style/Theme.NoTitleBaris a theme without an app bar. It was later called action bar in the code, e.g. in@android:style/Theme.Holo.NoActionBar. (title bar, action bar)- Navigation Bars in iOS on developer.apple.com (different purpose of navigation bar in iOS)
