Window (noun)

1. An opening in the wall or roof of a building or vehicle that is fitted with glass or other transparent material in a frame to admit light or air and allow people to see out.
2. A transparent panel in the cockpit of an aircraft through which the pilot can see outside.
3. A period of opportunity.
4. A graphical user interface element that displays the contents of a file or folder.
5. A transparent panel in a computer screen through which the user can see the desktop or the contents of an open application.

Origin:

Old english windǣge, from wind "wind" + ǣge "eye", of germanic origin; related to dutch and german fenster, from an indo-european root shared by latin ventus "wind".

Examples:

1. She looked out of the window.
2. He opened the window to let in some fresh air.
3. The window was broken and had to be repaired.
4. I'm sorry, the window for submissions has closed.
5. He maximized the window to see the whole document.