Learner's definition of WINDOW
1 a : an opening in a wall, door, etc., that usually contains a sheet of glass b : a sheet of glass that covers an opening in a building, vehicle, etc.
c : 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 d : an opening in a wall through which business is conducted
He used vinegar and water to wash the windows.
He accidentally broke a window.
Can you roll down the car window?
2 [count] : a part of something that you can see through 3 [count] : an area or box on a computer screen that shows a program that is currently running 4 [singular] : a period of time during which something can happen
The shuttle's launch has a window of only two days. [=it can only happen within two specific days]
The window of opportunity [=the time during which there is a chance to do something] has closed/ended.
a window into/on
: something that makes it possible to see or understand something clearly
go out the windowinformal
: to stop being used or thought about
throw (something) out the windowinformal
: to stop using or thinking about (something)