Dunno if this qualifies as 'unusual' or not; sure sounded interesting to me!

From the American Heritage Dictionary:

for the word "window":

"ETYMOLOGY: Middle English, from Old Norse vindauga : vindr, air, wind; see w- in Appendix I + auga, eye; see okw- in Appendix I.
WORD HISTORY: The source of our word window is a vivid metaphor. Window comes to us from the Scandinavian invaders and settlers of England in the early Middle Ages. Although we have no record of the exact word they gave us, it was related to Old Norse vindauga, “window,” a compound made up of vindr, “wind,” and auga, “eye,” reflecting the fact that at one time windows contained no glass. The metaphor “wind eye” is of a type beloved by Norse and Old English poets and is called a kenning; other examples include oar-steed for “ship” and whale-road for “sea.” Recently we have restored to the 800-year-old word window a touch of its poetic heritage, using it figuratively in such phrases as launch window, weather window, and window of opportunity or vulnerability."