What Makes a Classic Linux Desktop ‘Classic’?

Mostly, a classical desktop is defined as whatever you point at when you use the term. In the case of the LinuxQuestions Awards, I mean Cinnamon, KDE, LXDE, MATE, Trinity, and Xfce. I include KDE because, despite numerous innovations, its interface begins with a classical desktop.

Conversely, I exclude GNOME 3 and Unity because by default they deliberately omit major elements that all the desktops include that I would classify as classical: a single screen, a menu, and applets and/or icons to customize the panel and desktop.