noun, often attributive win·dow \ ˈwin-(ˌ)dō \
|Updated on: 15 Aug 2018

Definition of window

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 (such as glass) and capable of being opened and shut
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
2 : a means of entrance or access; especially : a means of obtaining information
  • a window on history
3 : an opening (such as a shutter, slot, or valve) that resembles or suggests a window
4 : the transparent panel or opening of a window envelope
5 : the framework (such as a shutter or sash with its fittings) that closes a window 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 window 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


play \ˈwin-dō-ləs, -də-\ adjective
out the window
: out of existence, use, or consideration

Examples of window in a Sentence

  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.

Recent Examples of window from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'window.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology 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

Other Building Terms

WINDOW Defined for English Language Learners


Definition of window for English Language Learners

  • : 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

WINDOW Defined for Kids


noun win·dow \ ˈwin-dō \

Definition of window for Students

1 : an opening in a wall to let in light and air
2 : the glass and frame that fill a window opening
3 : any of the areas into which a computer display may be divided and on which different types of information may be shown


  • a windowless room

History for 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

1 : fenestra 1
2 : a small surgically created opening : fenestra 2a
3 : 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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resembling the blue of the sky

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