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

Justice Amy Coney Barrett, however, supplied the argument’s most exacting skepticism, and likely the cleanest window into which a center-right majority might land.

From Slate • Apr. 10, 2026

“All of this is about placing it in the context of relevance for today, not just a window into the past,” she said.

From Los Angeles Times • Apr. 9, 2026

Two things can be true at once: Your very real fear of flying, which can result in very real physical and psychological distress, and your husband’s window of time to take this trip.

From MarketWatch • Apr. 9, 2026

During her life she secured more than 25 other permits, including for shoe-manufacturing equipment, improved window frames and sashes and a rotary engine.

From The Wall Street Journal • Apr. 9, 2026

He leaned over to talk to me through his passenger window.

From "Red Flags and Butterflies" by Sheryl Azzam