A name to attach to the origins of the manuscript

[Rafal]

Ergo the Voynich Manuscript's parchment, which is inarguably low-quality, would have been less expensive than the finer parchment used in higher-quality manuscripts.

I would have a very beginner question.
And yes, I am not ashamed to admit that physical aspects of manuscripts aren't my forte.  

Lisa, do you use "vellum" and "parchment" terms interchangeably?

Was Voynich Manuscript written on vellum or parchment?
Is vellum a kind of parchment? Or parchment a kind of vellum? Or are they separate things?