If you asked if the mind is zork or non-zork my question would be what is the definition of zork?
So, what are the definitions of material and non-material.?
First, be aware of the commonplace confusion between terms and their referents, and while we're discussing the important distinction, don't be misguided by yet another often confusion--that of the distinction between that which is a referent and meaning. You speak of definitions and yet even that too is not quite the same as meaning.
I won't embark on a journey to outline every distinction, but it's important to note that terms (or rather noun phrases) are composed of one or more words. For instance, the word, "cat" (and notice the double quote--which is a commonplace clarification that it is the word (and not the referent of the word, being discussed) (also often regarded as the use/mention distinction) is a one-worded term. In comparison, the term "free will" is a two-worded term.
My cat is fat. I spoke of my cat. I did not speak of the word "cat". In fact, I used (used, I say) the word, "cat". Now, the word, "cat" has three letters. In this instance, I mentioned (mentioned, I say) the word, "cat".
Now, let's look at a real-world example. The name of my cat is, "crooked tail kitty." That's a three-worded term by the way. Do you think the name of my cat is hungry? Bet not! The referent to the term, namely my actual purring, couch-clawing cat is hungry--always, go figure! The point is that we must be very focused on exactly what it is we're talking about.
Granted, we often talk in what can be regarded as short-hand, so if you were to ask me aloud to spell cat, I (and most others) would readily understand that you wanted me to spell the word--certainly not cat. Despite this, in philosophy, where confusion is abound, it often becomes quite necessary to expound with remarkable precision so as to avoid further misunderstanding.
With that in mind (whatever that is, right!), rest assured that there is a difference between material and "material". One is a word, and one is not. With that in mind, let it be understood that it is always the word (and never the referent of words) that have definitions.
Your question, if to be taken as if not written in short-hand makes a category error, yet with my explanation prefacing my response, I will assume that you desire the definition of the word. Interesting. Like many words, the written definitions are housed in dictionaries, and they are explanations that help us glean their meaning--there lexical meaning--as collectively used by fluent speakers of our language.