After executing the Emacs binary I see on a screen (what in common sense is called a window) an Emacs-frame.
An Emacs-frame has the [-] [+] [x] icons in the title bar, a menu, a toolbar, a status-bar and provides the possibility of creating multiple tabs I refer here to as Emacs-frame-tabs in order to be able to distinguish them from the tabs which are Emacs-window-tabs.
An Emacs-frame-tab covers the entire free space of the Emacs-frame not occupied by bars or the minibuffer ...
By the way: is a minibuffer an Emacs-window or an Emacs-frame-tab with restricted user access for creating tabs and windows, or just an own independent element???
... and allows to create multiple Emacs-windows in that free space.
Emacs Options Menu "Show/Hide" comes with an option to display in any Emacs-window an Emacs-window-tab-bar (called in the Menu: Window Tab Line).
It seems that the Emacs-frame-tab-bar and Emacs-window-tab-bar displays in the tabs the names of Emacs-buffers.
An Emacs-buffer is an elisp object which represents all of the data required to generate a visualization of the data in an Emacs-window, which can, but not need to be some text loaded from a file in order to edit it.
As you see from the above I have created an own way of describing the structure of what Emacs comes with and the term "Emacs-frame-tab" for which I haven't yet found any Emacs-native word.
Is there anyone here able to give a better structured description of the visual perceivable elements Emacs comes with?
Or is my naive approach to create an own "Emacs language" necessary to be able to keep the concepts apart and understand them, the currently best existing explanation of the hierarchical structure of the elements of Emacs GUI (Graphical User Interface elements)?