Windows are rectangular display areas that open on screens.  The window
acts as a virtual terminal allowing a program to interact with the user as
if it had the entire display all to itself.

Each window opens on a specific screen and takes certain characteristics,
such as resolution, colors and display attributes, from that screen. These
values cannot be adjusted on a window by window basis.  Other window
characteristics such as the text font are inherited from the screen but
can be changed.

An application may open several windows at the same time on a single
screen.  The Workbench and other public (shareable) screens allow windows
opened by different applications to coexist on the same screen.

Windows are moveable and can be positioned anywhere within the screen on
which they exist.  Windows may also have a title and borders containing
various gadgets for controlling the window.

 Window System Gadgets    The Active Window