Merriam-Webster Collegiate Dictionary - window

 noun  Usage: often attributive  Etymology: Middle English ~e, from Old Norse vindauga, from vindr wind (akin to Old English wind) + auga eye; akin to Old English eage eye — more at eye  Date: 13th century  1.  a. an opening especially in the wall of a building for admission of light and air that is usually closed by casements or sashes containing transparent material (as glass) and capable of being opened and shut  b. ~pane  c. a space behind a ~ of a retail store containing displayed merchandise  d. an opening in a partition or wall through which business is conducted a bank teller's ~  2. a means of entrance or access; especially a means of obtaining information a ~ on history  3. an opening (as a shutter, slot, or valve) that resembles or suggests a ~  4. the transparent panel or opening of a ~ envelope  5. the framework (as a shutter or sash with its fittings) that closes a ~ opening  6. chaff 4  7. a range of wavelengths in the electromagnetic spectrum to which a planet's atmosphere is transparent  8.  a. an interval of time within which a rocket or spacecraft must be launched to accomplish a particular mission  b. an interval of time during which certain conditions or an opportunity exists a ~ of vulnerability  9. an area at the limits of the earth's sensible atmosphere through which a spacecraft must pass for successful reentry  10. any of various rectangular boxes appearing on a computer screen that display files or program output, that can usually be moved and resized, and that facilitate multitasking  • ~less adjective