The AWT defines two different kinds of containers, panels and windows.
Panels are subclasses of java.awt.Panel. A panel is
contained inside another container, or perhaps inside the web
browser's window. Panels do not stand on their own. Applets are
panels.
Windows are subclasses of java.awt.Window. A window
is a free-standing, native window. There are two kinds of windows:
frames and dialogs. A frame is an instance of a subclass of
java.awt.Frame. It represents a normal, native window. A
dialog is a subclass of java.awt.Dialog. A dialog is a
transitory window that exists merely to impart some information or
get some input from the user.