Over the years science fiction fandom has developed its own specialized vocabulary, either to express concepts not found in the mundane world, or to avoid undue repetition of commonly used expressions by substituting suitable acronyms. Some fanspeak terms eventually found their way into general usage, such as the word fanzine, first "officially" defined in the 1978 edition of the Randon House Dictionary. Similarly, many of the acronyms (such as HHOK) have today become part of popular Internet chatroom and news group usage.
On the other hand, many formerly common fannish expressions have become obsolete as new personalities, issues and technologies have replaced the old ways. Twonk's Disease, for example, referred to the soreness in back and arm muscles that results from operating a hand-cranked mimeograph or ditto machine over a long printrun. No one prints fanzines by hand anymore, however, so Twonk's Disease is no longer a commonly shared experience, and the term has fallen out of use.
The following, then, provides a basic glossary of fan jargon still in use today.