Window
From Wikipedia, a free encyclopedia written in simple English for easy reading.

A window of a house in England
A window is an opening within a wall of a building, in a car etc., to let air and light in. It is usually filled with a sheet of glass. They can be many different shapes, including rectangular, square, circular, or irregular shapes.
In a operating system similar to Microsoft Windows or Mac OS, a window is a part of a screen that displays some data to a user. There are many different windows, for example web browser. You use it now.
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