At one point, Lunaescence had a large dictionary of fanfiction, gaming, and Japanese terms. It was taken down because it was hogging site resources. As it has not been replaced yet, I felt the need to make a short equivalent. Though not as thorough as the site dictionary was, I hope this helps people in some small way.
There are currently five chapters of terms, which are divided by subject and arranged alphabetically within their own chapter. The one exception to this is the Japanese terms chapter, which is arranged into three subsections: general terms, weapons, and honorifics.
Much thanks to Jasson and Sally for the original dictionary, to Tikatu who contributed to it, and to DG for helping with the chapter on Japanese terms. If you're going to use Japanese in a story beyond very basic phrases and don't speak the language with any fluency yourself, please refer to the forum thread on translation help.