Fen

The plural, genderless form of "fan". This is fan jargon, formed by a tongue-in-cheek analogy to the pluralization of "man" as "men". For when 'Fans' just won't cut it.

Certain aspects of fandom, especially early SF fandom, preferred this term to "fans," hoping to distinguish from, for example, sports fans.

Also, and perhaps not coincidentally, a synonym for "swamp".

Literature

 * Bimbos of the Death Sun by Sheryn McCrumb uses the term in order to refer to fans.

Live-Action TV

 * In an episode of Crusade, a race called the "Fenn" is discovered to live in hyperspace. One character describes them as "harmless, and attracted by shiny objects." Knowing J. Michael Straczynski, it's got to be deliberate.
 * Not only that, they're said to be "barely sentient" and "lose interest quickly". Take That much?
 * .... And when they start humping the ship's leg?
 * In the Fenn's defense, Gideon did order the helsman to increase thrust in response.

Web Original

 * The fiction community/writing collective project Fenspace is named after this trope.

Real Life

 * The origin of the slang term Fench - Fen Stench. It specifically refers to the odor of any large fantasy or sci-fi con towards the latter half, as many fen decide they don't need to sleep during the con - or shower, either.