Dictionary Meaning and Definition on 'Oclock'
Wikipedia Meaning and Definition on 'Oclock'
In the X Window System, the shape extension allows windows to be given arbitrary, non-rectangular shapes.
Two well-known applets that use the shape extension are oclock, which is a simple round analog clock, and xeyes, which shows two googly eyes that follow the cursor on the screen as if they were watching it. Most X Window systems have one or the other (or both) in their standard installations. In addition, some window managers use the shape extension to draw non-rectangular icons.
Applications can only create rectangular windows, but can then change their shape to be an arbitrary part of the original rectangle. The remaining area of the rectangle is not only transparent (shows what is below the window); rather, it is not part of the window at all. For example, if a window is shaped with a hole in the middle, not only the hole shows what is below the window, but a click in the hole is considered to be a click in what is below the window.[See more about Oclock at Dictionary 3.0 Encyclopedia]