w

window gravity

When windows are resized, subwindows can be repositioned automatically relative to some position in the window. This attraction of a subwindow to some part of its parent is known as window gravity.

window manager

Manipulation of windows on the screen, and much of the user interface (policy) is typically provided by a window manager client.

window manager shell

A subclass of shell called wm-shell that interacts with the window manager.