Here is what Wikipedia has to say about windows.
A window is an opening in a wall (or other solid and opaque surface) that allows the passage of light and, if not closed or sealed, air and sound. Windows are usually glazed or covered in some other transparent or translucent material. Windows are held in place by frames, which prevent them from collapsing in.
The word Window originates from the Old Norse ‘vindauga’, from ‘vindr – wind’ and ‘auga – eye’, i.e. "wind eye". In Norwegian Nynorsk and Icelandic the Old Norse form has survived to this day (in Icelandic only as a less used synonym to gluggi), while Swedish has kept it—mostly in dialects—as ‘vindöga’ (‘öga – eye’). Danish ‘vindue’ and Norwegian Bokmål ‘vindu’ however, have lost the direct link to ‘eye’, just like window has. The Danish (but not the Bokmål) word is pronounced fairly similar to window.
Window is first recorded in the early 13th century, and originally referred to an unglazed hole in a roof. Window replaced the Old English ‘eagþyrl’, which literally means ‘eye-hole,’ and ‘eagduru’ ‘eye-door’. Many Germanic languages however adopted the Latin word ‘fenestra’ to describe a window with glass, such as standard Swedish ‘fönster’, or German ‘Fenster’. The use of window in English is probably due to the Scandinavian influence on the English language by means of loanwords during the Viking Age. In English the word fenester was used as a parallel until the mid-1700s and fenestration is still used to describe the arrangement of windows within a façade.
And to illustrate that window can be a metaphor for non-architectural thoughts, here are some quotes for your rumination:
Birth is the sudden opening of a window, through which you look out upon a stupendous prospect. For what has happened? A miracle. You have exchanged nothing for the possibility of everything. Willie Dixon
I'm just a landscape painter. I look out the window and I see what's going on, and I paint it. While I'm painting it, I also write thoughts about what I see going on out there. William Wiley
A smile is a light in the window of your face to show your heart is at home. Anonymous
Now Allah has created the dream not only as a means of guidance and instruction, I refer to the dream, but he has made it a window on the Unseen. Mohammed
A smile is a light in the window of the soul indicating that the heart is at home.
OK, Brenda, you can now get to work on the next challenge!!