"It used to mean a certain flavor of fanfic, as far as I know, and included some f/f pairings (Xena, anybody?). Is it now, with original characters, assumed to be only m/m written by women?" No, it's the other way round. When slash began in the 1970s, it was only m/m. Femslash came later, and it was - is - resisted by some old-timers who believed that the term "slash" should be reserved for m/m pairings. However, I think that's a minority viewpoint now. Original slash has not yet received the degree of acceptance that femslash has. My local slash con, for example, refuses to include an original slash category in its zine awards. It's not that anyone objects to slashy original fiction; there are just a lot of folk who believe that the term slash should be reserved for fan fiction. As for gender, in the 1970s and 1980s, according to the sociologists who were studying this, slash was almost 100% female-written. That's less true today, but (as you probably know) it's still a female-dominated genre, just as genre romance is. "we-know-it-when-we-see-it" Exactly. :) I've had the interesting experiment of marketing my e-zine's stories to slash folk. Most of these stories were most definitely not written for the slash world - they're gay porn. But since I picked the stories, and I have slashy tastes (among other things), these stories are receiving praise from slash readers. On the other hand, I've seen some poor gay porn author wander unsuspecting onto a slash forum, post a jerk-off tale that what would be perfectly acceptable at a gay porn forum, and get roundly booed. So I do think there's a difference between slash and gay porn (maybe less so between slash and gay non-erotic fiction), but there's a lot of overlap too. If I had to pick, I would say that the non-slash genre that is closest to slash is SF/F. Slash grew out of SF/F fandom, after all, and even in the contemporary stories, you can see slashers using conventions that are also used in SF/F.