I've also noticed that some people consider "pure perl" to be the same as "core perl" - that is, just the modules that come with perl itself. This definition has annoyed me, but I thought it worth pointing out. This definition, which is closer to your guess, still allows for "use" directives - as long as what you're using comes with perl itself, such as File::Copy or File::Spec or even, on Windows, Win32.