noun, win·dow often attributive \ˈwin-(ˌ)dō\

: an opening in a wall, door, etc., that usually contains a sheet of glass

: a sheet of glass that covers an opening in a building, vehicle, etc.

: a large window at the front of a store where goods are displayed so that they can be seen by people who are walking past

Full Definition of WINDOW

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 :  windowpane
c :  a space behind a window of a retail store containing displayed merchandise
d :  an opening in a partition or wall through which business is conducted <a bank teller's window>
:  a means of entrance or access; especially :  a means of obtaining information <a window on history>
:  an opening (as a shutter, slot, or valve) that resembles or suggests a window
:  the transparent panel or opening of a window envelope
:  the framework (as a shutter or sash with its fittings) that closes a window opening
:  chaff 4
:  a range of wavelengths in the electromagnetic spectrum to which a planet's atmosphere is transparent
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 window of vulnerability>
:  an area at the limits of the earth's sensible atmosphere through which a spacecraft must pass for successful reentry
:  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
win·dow·less \-dō-ləs, -də-\ adjective
out the window
:  out of existence, use, or consideration

Examples of WINDOW

  1. She opened a window to let in some air.
  2. I looked out the window and saw a deer.
  3. He used vinegar and water to wash the windows.
  4. He accidentally broke a window.
  5. Can you roll down the car window?
  6. The windows along 5th Avenue were all decorated for Christmas.
  7. I saw a beautiful dress in the window.
  8. He sits behind a window and sells movie tickets.
  9. Make sure the address shows through the window in the envelope.
  10. A window opened in the fog and we could finally see the ocean.

Origin of WINDOW

Middle English windowe, from Old Norse vindauga, from vindr wind (akin to Old English wind) + auga eye; akin to Old English ēage eye — more at eye
First Known Use: 13th century

Other Building Terms

batten, cistern, hearth, lath, transom, wainscot
WINDOW Defined for Kids


noun win·dow \ˈwin-dō\

Definition of WINDOW for Kids

:  an opening in a wall to let in light and air
:  the glass and frame that fill a window opening
:  any of the areas into which a computer display may be divided and on which different types of information may be shown
win·dow·less adjective <a windowless room>

Word History of WINDOW

To people living in cold regions around the world, a window in a house was only practical when glass became available to provide light while sealing out the weather. As a result, in English and other languages of northern Europe, words for window appear relatively late, after glass was introduced from southern Europe. In Old English, window was ēagduru, literally eye-door, or ēagthyrel, eye-hole—since a window, like an eye, is a means of seeing out. The word window itself comes from a word vindauga in Old Norse (the language of the Vikings) that means literally wind-eye.
Medical Dictionary


noun win·dow \ˈwin-(ˌ)dō, -də(-w)\

Medical Definition of WINDOW

:  fenestra 1
:  a small surgically created opening :  fenestra 2a
:  a usually narrow interval of time or range of values for which a certain condition or an opportunity exists <coma and multiorgan failure can occur within hours and there may be a very narrow window of opportunity for transplantation—J. P. A. Lodge>—see therapeutic window
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