CMS pages and sections where you administer parts of your website.
The Administration Screen is referring to different areas of your site’s WordPress administration area.
WordPress has referred to this as ‘Screens’ rather than ‘Pages’ to avoid confusion between the post type ‘Pages’, as these can be edited and created etc.
What do they look like?
Any administration screens have the horizontal admin bar across the top and the vertical menu bar on the left. It’s pretty much everywhere within the admin area.