Frankencode - (mass noun) - Sources to an application that, for some reason, are written in more than one programming language. Generally considered problematic within the geek community because it significantly reduces the number of programmers eligible to work on the project, and even for those skilled in all languages involved, cross-language issues make the code unwieldy, introduce avenues for subtle bugs, and often make debugging really difficult.

That's my contribution to Geek jargon. With any luck, it will eventually enter mass use, and maybe make it into The Jargon File. I'm not stomping on any toes -- Google searches for frankencode, as I write this, shows only 3 or 4 instances on the web (!!).