"Ubuntu" - is Vanilla Ubuntu.

Kubuntu, Lubuntu, Xubuntu and Mint are all derivatives of this. However, in their own right, they are Vanilla too.

If you want to be extremely technical, Vanilla Ubuntu is a fresh install with no extra packages installed and no changes made.

In a broader sense, Vanilla Ubuntu can refer to Ubuntu (the OS) as opposed to any derived OS, or to Ubuntu (the OS) with any of the officially supported Desktops (KDE, LXDE or XFCE), but without any third party software (that is, software from a source other than the official repositories.

Vanilla Ubuntu cannot refer to:

• Ubuntu with all proprietary or closed source components removed (like GNUSense).
  
  
  
  • This is a derivative, and also consists of removing packages and keeping a strict rule of free software only.
  
  


• A remaster of any kind.


• Ubuntu with a customized UI (at the code level).
  
  
  
  • Customizing at the code level invalidates the "Vanilla nature" of the OS.