the small button with an X in it which appears at the right hand end of the title bar in recent versions of Windows and OS/2.
The small button on a window's Title bar which, when clicked, closes the window.
A close button is normally found in the top right hand corner of a window or graphical user interface. A close button is normally a square with an 'x' inside it.
A button at the top-right corner of every window and box which appears in Microsoft Office. It automatically closes that particular window or box.
The X in the upper right corner of a window. When clicked, it will close the current window.
A cross button at the top right corner of a window or on a software window. Click this button to close a window or terminate software.
A button in a window's title bar that, when clicked on, closes the window. When the close button is partially drawn, it means that the window contains unsaved changes or that its contents aren't up to date.