From the Dungeon to the Dictionary

Neat, I wonder what other genre/hobby created words are in regular use. [Link]

I recently received an e-mail from a correspondent who noted that my list of forms of government lacked the word magocracy. I was slightly bewildered that it was not there, for two reasons. I'd thoroughly searched the online Oxford English Dictionary and other sources for all "-cracy" and "-archy" words, so in theory, there shouldn't be any omissions. What's more, it was a word that had been familiar to me for many years. You can imagine, then, my chagrin when I determined that there is no such word - at least, not in any dictionary. That is to say, magocracy is properly *magocracy, using the linguist's convention of an asterisk to represent irregular, improper or non-existent words.

This revelation left me, if not shaken to my lexicographic foundations, then at least perplexed that I had possessed in my vocabulary for many, many years a word that simply did not exist. This admission is rather embarrassing for someone who takes great pride in his knowledge of obscure English vocabulary. How could this happen?