Dictionary.net

/filk/ [SF fandom, where a typo for "folk" was adopted as anew word] A popular or folk song with lyrics revised orcompletely new lyrics, intended for humorous effect whenread, and/or to be sung late at night at SF conventions.There is a flourishing subgenre of these called "computerfilks", written by hackers and often containing rathersophisticated technical humour. See double bucky for anexample. Compare grilf, hing and newsfroup.