window

American  

[win-doh] / ˈwɪn doʊ /

noun

1. an opening in the wall of a building, the side of a vehicle, etc., for the admission of air or light, or both, commonly fitted with a frame in which are set movable sashes containing panes of glass.

2. such an opening with the frame, sashes, and panes of glass, or any other device, by which it is closed.

3. the frame, sashes, and panes of glass, or the like, intended to fit such an opening.

   Finally the builders put in the windows.

4. a windowpane.

5. anything likened to a window in appearance or function, as a transparent section in an envelope, displaying the address.

6. a period of time regarded as highly favorable for initiating or completing something.

   Investors have a window of perhaps six months before interest rates rise.

7. Military. chaff.

8. Geology. fenster.

9. Pharmacology. the drug dosage range that results in a therapeutic effect, a lower dose being insufficient and a higher dose being toxic.

10. Aerospace.

    1. launch window.

    2. a specific area at the outer limits of the earth's atmosphere through which a spacecraft must reenter to arrive safely at its planned destination.

11. Computers. a section of a display screen that can be created for viewing information from another part of a file or from another file.

    The split screen feature enables a user to create two or more windows.

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verb (used with object)

1. to furnish with a window or windows.

2. Obsolete. to display or put in a window.

window British  

/ ˈwɪndəʊ /

noun

1. a light framework, made of timber, metal, or plastic, that contains glass or glazed opening frames and is placed in a wall or roof to let in light or air or to see through

2. an opening in the wall or roof of a building that is provided to let in light or air or to see through

3. See windowpane

4. the display space in and directly behind a shop window

   the dress in the window

5. any opening or structure resembling a window in function or appearance, such as the transparent area of an envelope revealing an address within

6. an opportunity to see or understand something usually unseen

   a window on the workings of Parliament

7. a period of unbooked time in a diary, schedule, etc

8. short for launch window weather window

9. physics a region of the spectrum in which a medium transmits electromagnetic radiation See also radio window

10. computing an area of a VDU display that may be manipulated separately from the rest of the display area; typically different files can be displayed simultaneously in different overlapping windows

11. (modifier) of or relating to a window or windows

    a window ledge

12. informal dispensed with; disregarded

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verb

1. (tr) to furnish with or as if with windows

window Idioms  

1. see out the window.

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Other Word Forms

• unwindowed
  adjective
• well-windowed
  adjective
• windowless
  adjective
• windowy
  adjective

Etymology

Origin of window

1175–1225; Middle English windoge, windowe < Old Norse vindauga, equivalent to vindr wind ¹ + auga eye

Explanation

A window is an opening in a wall that you can see through. Most windows are fitted with glass and can be opened to let air flow through them on a warm spring day. Buildings have windows so that the sun can brighten up indoor spaces during the day. You can also use window to mean just the glass pane inside the frame: "Sorry that my baseball broke the window!" Cars have windows too, which can be rolled up and down, and department stores use their large windows to display items for sale. And on a computer, a window is an area containing information that's enclosed by a window-like "frame."

Example Sentences

Window reflections have been misconstrued as a possible intruder and a tornado.

From The Wall Street Journal • May 5, 2026

“I would never compare myself with Hitchcock, but it’s almost like ‘Rear Window.’

From Los Angeles Times • Nov. 20, 2024

The Window Kid from Arnold, known to friends as Greg, has been a regular customer of the Lace Market Fish Bar for years.

From BBC • Oct. 26, 2024

Window coatings used in many recent studies are optimized for light that enters a room at a 90-degree angle.

From Science Daily • Apr. 2, 2024

The Authority Suit at Window 3 reels us in with a beckoning finger.

From "Internment" by Samira Ahmed