Middle English windowe, from Old Norse vindauga, from vindr wind (akin to Old English wind) + auga eye; akin to Old English ēage eye
A 'wind eye'. The Korean word for window is changgu (창구, 窓口), made up of the Chinese characters chang (窓), meaning surface or exterior, and gu (口) meaning mouth and, by extension, a opening. An 'opening in the exterior' of a building.
Make of that what you will.