Using a term wrong, and what determines whether it is "wrong" or not

I'm sitting here doing a project for my research methods class in which we are supposed to find definitions of 50 conceptual terms we will use in our own research, and then rewrite our own definitions of these terms. Although I initially thought it wouldn't be that bad, it is an exceedingly difficult project. A lot of times, I don't really know what a term means precisely, so I look it up and use it with that definition in mind. It's kind of hard to rewrite the definition when I'm only just finding out what it means. But this is an important thing to do as a scholar. So, I just looked up "an" official definition of intertextuality, which I have been using with great abandon in my thesis, and discovered that according to Graham Allen at University College Cork in the (online) Literary Encyclopedia, http://www.litencyc.com/php/stopics.php?rec=true&UID=1229, I have been using the term quite wrong.

Here is part of what he says:
“The fundamental concept of intertextuality is that no text, much as it might like to appear so, is original and unique-in-itself; rather it is a tissue of inevitable, and to an extent unwitting, references to and quotations from other texts. These in turn condition its meaning; the text is an intervention in a cultural system…. [That's all fine, but here's the rub:] [I]ntertextuality should not be, but frequently is, used to refer to literary relations of conscious influence…. Intertextuality should not be, but frequently is, used to refer to the intentional allusion (overt or covert) to, citation or quotation of previous texts in literary texts.” He goes on to say that we need to look at what the post-structuralist theorists like Kristeva and Barthes originally meant to understand how to use the term.

I agree that we should be precise in our definitions, and I wouldn't mind terribly going back and changing my terminology to "allusion" etc., although I'm not quite sure when something in the novel is conscious or unconscious allusion. However, this makes me wonder, how much freedom we have (as graduate students especially) to use a term in the way we want to use it, as long as we qualify this at the beginning, and how much we should try to stick to the definitions given by other people (or the original intentions of the term.) Obviously, words and terms evolve and change meaning; however, I don't want to use that as an excuse for sloppy scholarship. If everyone used words any old way they wanted, then the words would have no meaning (of course, it's ironic that I'm having this dilemma with a word that emerged in post-structuralist theory, since my understanding of post-structualist theory would lead me to believe that this is precisely the problem: definition and meaning is slippery because there is no absolute defining Platonic centre, in which THIS is the meaning and THAT is not). However, in practical terms, and as a graduate student, I realize that sometimes we have to pretend that we mean the same thing, even if we use slightly different words to reach at that meaning.

I suppose I should probably look at a few more definitions before I go chopping it out of my thesis. But I can see why this is a useful project for us to do in our Research methods class.

Source
Graham Allen, University College Cork. “Intertextuality.” The Literary Encyclopedia. 24 Jan. 2005. The Literary Dictionary Company. 9 October 2006. http://www.litencyc.com/php/stopics.php?rec=true&UID=1229 Downloaded 9 October 2006