Speculative fiction, otherwise known as spec fic and often used interchangeably with SFF, is my genre. So a decent start on a definition scavenged from my random reading of writing/publishing industry material:
Speculative fiction is an umbrella term encompassing the more fantastical fiction genres, specifically science fiction, fantasy, horror, weird fiction, supernatural fiction, superhero fiction, utopian and dystopian fiction, and alternate history in literature as well as related static, motion, and virtual arts.
This is cited as coming from Wikipedia, but I found it on an interesting website called Science Fiction and Other ODDyssies.
