the term "fan fiction" has been used in print as early as 1939; in this earliest known citation, it is used in a disparaging way to refer to amateurish science fiction (as opposed to "pro fiction"). the term also appears in the 1944 "fancyclopedia", an encyclopedia of fandom jargon. it is defined there as "fiction about fans, or sometimes about pros, and occasionally bringing in some famous characters from [science fiction] stories". the book also mentions that the term is "sometimes improperly used to mean fan science fiction, that is, ordinary fantasy published in a fan magazine".