When naming different components in a layout what is considered a panel and what is a pane?
A pane is a section of a window. For a physical example, a paned window is a window that is divided into sections known as panes. Originally, the meaning pertained to sectioned glass windows in walls. (Wikipedia) It is a layer in the build-up of a GUI.
A panel is a flat, physical area, usually containing controls, receptacles, a display such as an LED or LCD screen, or allowing users to remove it for access to whatever lies behind it. A screen is, technically, a physical, displaying area of a panel. Panels may or may not have a visible border.
Thus, panes in MS Word application would include the title bar where it shows the names of file and of the application, a menu bar, a "ribbon" bar, the editing area, a status bar, and optional ruler bars. It's what you get, for example, if you drag the splitter bar in a Word window.
Microsoft uses "task pane" to designate an area sectioned off from the main area of an application and used for some function.
Check these examples: