A window is a rectangular area in which you can place other visual entities for which you have declared variables.
When you open a window and no other windows are open, the new window is inside the screen window, which has the basic characteristics of any window in the operating system. This is not the case in UNIX when the Curses library is in use; there the display of a Console UI window puts the existing terminal window into windowing mode.
Any additional window that you open is displayed in the content portion of the screen window, usually on top of the window that you already opened. A side-by-side presentation of windows is also possible.
When you declare a window, you can set various properties. For example, the position property is the location relative to the upper left corner of the display, and the size property sets the window's height and width in characters. You can use variables and literal values to specify both size and position.
myWindow WINDOW
{name="myWindow", position = [2,2],
size = [18,75], color = red, hasborder=yes};