- (dated, fandom slang) The activity of fans, particularly of science fiction.
- 1977, Brian Ash, The Visual encyclopedia of science fiction, Harmony Books, page 274
- It must be emphasised that this was genuinely a 'historical' action; letter-writing to the prozines is currently a discouraged area of fanac.
- 2002, Mike Resnick, Once a Fan..., Wildside Press LLC, page 274
- The advent of the computer and the modem means that an increasingly large number of fans indulge in most of their fanac online.