A window is a rectangular display area that provides a view of the virtual screen. It can be any size, including the entire screen. It is usually framed. Depending on the window type and the underlying system software, windows are displayed in either graphical or text-mode. Windows can include a number of other interface objects, such as a title bar, menu bar, and controls.
In GUI environments, windows are the fundamental construct used to display and accept commands and data from the user.
The Printers window from the Windows 95 Control Panel