Noun

1. (trademark) an operating system with a graphical user interface
2. A framework of wood or metal that contains a glass windowpane and is built into a wall or roof to admit light or air
3. A transparent opening in a vehicle that allow vision out of the sides or back; usually is capable of being opened
4. A transparent panel (as of an envelope) inserted in an otherwise opaque material
5. An opening that resembles a window in appearance or function
6. The time period that is considered best for starting or finishing something
7. A pane of glass in a window
8. An opening in a wall or screen that admits light and air and through which customers can be served
9. (computer science) a rectangular part of a computer screen that contains a display different from the rest of the screen