Pane and panel
A pane is a (usually) independently scrollable subsection of a window. It’s what you get, for example, if you drag the splitter bar in a Word window.
A panel is an object that is used to group controls and other objects. It is often but not always dragable, occasionally resizable or scrollable. Most toolbars, for example, consist of a panel with buttons. Panels may or may not have a visible border.