Window managers are singular programs meant purely for defining and managing the behavior of windows, window decorations, though it can provide extras like compositing, it's still one program. When standalone they might also provide simple panels and a desktop menu, but not always (Like TWM.)

Desktop environments are a whole new mammal from window managers. Window managers are a mere COMPONENT of a desktop environment. Indeed, GNOME isn't a window manager, but it has and uses a window manager called Metacity. KDE also has its own window manager built specifically for use in KDE called KWin. However, a desktop environment is a huge SUITE of programs from a desktop manager, widget system, panels, file manager, settings manager, settings daemon, window manager, and usually a lot of extras like games, media players, web browsers, IM clients, e-mail clients (Usually with both POP3 and IMAP support.),

Window managers are singular programs meant purely for defining and managing the behavior of windows, window decorations, though it can provide extras like compositing, it's still one program. When standalone they might also provide simple panels and a desktop menu, but not always (Like TWM.)

Desktop environments are a whole new mammal from window managers. Window managers are a mere COMPONENT of a desktop environment. Indeed, GNOME isn't a window manager, but it has and uses a window manager called Metacity. KDE also has its own window manager built specifically for use in KDE called KWin. However, a desktop environment is a huge SUITE of programs from a desktop manager, widget system, panels, file manager, settings manager, settings daemon, window manager, and usually a lot of extras like games, media players, web browsers, IM clients, e-mail clients (Usually with both POP3 and IMAP support.),