This is the 12726th most frequent German word.
windows
The German word for "windows" is "Fenster," meaning openings in a building or vehicle that allow light and air to enter.
In this sentence, 'Windows' refers to the operating system developed by Microsoft.
Das Programm läuft nicht gut unter Windows 10.
The program does not run well on Windows 10.
This usage of 'Fenster' again refers to the physical windows, particularly those made of glass.
Durch die Glasfenster konnten wir die Aussicht betrachten.
Through the glass windows, we could enjoy the view.
Here, 'Fenster' refers to a physical window, which is a typical glass opening in a wall.