AU - Alternate Universe; in AU fics, there are various deviations from canon. These can be anything from a "What if this had happened, instead of this?" scenario to one which places the cast in an entirely different universe...hence the name.

• Fiction that is intentionally bad, written that way for the purposes of entertaining and amusing, and also educating, by pointing out some of the most common errors made by inexperienced writers.
• Fiction that is unintentionally bad; the author thinks it's good. Often those of us who know the difference between good and bad fic don't know whether to laugh or cry when we read this kind of story.

Canon - The original source material (manga, anime, etc). This is where fic authors draw their facts from. For example, in Gravitation, Shindou Shuichi is Bad Luck's singer. This is a canon fact.

Crossover - A story which combines characters/settings/etc from two or more series.

Deathfic - Fic in which one (or more) character dies, either during the fic, or sometime before.

Femmeslash - A term for female/female pairings in a fic.  Used more in non-anime/manga fandoms.

Gen - Short for 'general'; a type of fic that doesn't focus on romance/pairings.

Het - Short for 'heterosexual'; hence, includes a male/female pairing.

IC - In Character; that is, the characters' actions/thoughts/etc are believable, and consistent with their canon personality.

OC - Original Character; pretty self-explanatory.

OOC - Out of Character; that is, the characters behave in a way that contradicts their canon personality. (i.e., Saiyuki's Sanzo being very meek, timid, and quiet.  That's way OOC!)

Pairing - Two characters that are romantically involved.

POV - Point of View; if the story is written in first person, this indicates whose perspective it is from.

PWP - Plot, What Plot?  Alternately, Porn Without Plot.  Indicates a story without a plot.

Shoujo Ai - Lit. "Girl's Love", shoujo ai stories feature girl/girl pairings.  Though usually not as explicit as yuri, the two terms are sometimes used interchangeably, no matter the content.  Used mostly in anime/manga fandoms.

Shounen Ai - Lit. "Boy's Love", shounen ai stories feature boy/boy pairings.  Though usually not as explicit as yaoi, the two terms are sometimes used interchangeably, no matter the content.  Used mostly in anime/manga fandoms.

Slash - A term for male/male pairings in a fic.  Used more in non-anime/manga fandoms.

Spoilers - A piece of information which can reveal (thereby "spoil") an important plot point in a movie, show, issue, etc. that the reader has not yet seen/read.

TWT - Timeline, What Timeline?  Indicates a story that doesn't fit in the canon timeline.

WAFF - Warm And Fuzzy Feelings; describes any cute, sappy fic, sometimes but not always involving g-rated romance.

WIP - Work In Progress; an unfinished story, which could be anywhere from updating regularly to assumed scrapped.

Yaoi - Male/male relationships, often graphic.  Though usually more explicit than shounen ai, the two terms are sometimes used interchangeably, no matter the content.  Used mostly in anime/manga fandoms.

Yuri - Female/female relationships, often graphic.  Though usually more explicit than shoujo ai, the two terms are sometimes used interchangeably, no matter the content.  Used mostly in anime/manga fandoms.