As with any subculture, fandoms have their own language for referring to the things that their community interacts with or creates. Fans coin terms to refer to the things that come up most often in their discussions about their base media.
There are many terms and phrases that are specific to individual fandoms, but given that there are quite a few of these, I think it’s best that, for now, we stick to the terms most often used in wider fan culture across media.
Let’s define some terms.
Canon — Something that is “canon” happens on-screen or in the text of the original work. It’s something that was officially stated, written, or condoned by the licensed creators. It’s a reuse of the larger literary term academics use to describe the “proper” or “official” bodies of literature, the “literary canon.”
Headcanon — Headcanons are beliefs or story tidbits held by a single fan. They’re not considered actually canon until they’re confirmed, but they’re things that fans like to believe are true about the series or its characters. Popular headcanons include what characters do in their downtime, how characters might react to out-of-canon situations or unconfirmed fan theories about storylines.
Fanon — This is where the line gets a little blurred. The “fanon” of a work is the fandom’s more widely accepted headcanons, meaning that, while a large majority of fans may like or approve of the idea, it’s not officially confirmed by the original creators.
Stan — To stan someone or something is to support and be a solid fan of them or it. It’s usually used in a somewhat-joking manner to mean that you’re a “superfan” of a particular character, actor, or situation.
AU — “Alternate Universe.” This term is used when the setting of a piece of fan media, from headcanons to full-on fiction and artwork, is different from the source media but retains many of its identifying features, usually in the form of characters adapted to fit the new setting.
OOC — “Out of Character,” meaning that the character, either in a piece of fan writing or occasionally in the source media, is acting in a way that is contrary to their usual characterization or doesn’t make sense for their usual personality. For instance, if a usually stoic character suddenly has an emotional breakdown with no warning, this might be called out as OOC. Sometimes this is done intentionally by fan writers and artists who want to create something fun with the image of the character that doesn’t necessarily align with their canon personality, as in an AU.
OC — Not to be confused with OOC, this means “Original Character.” An original character is a character created by a fan that does not appear in the original canon but generally follows the rules of the canon’s world.
Mary Sue — This is a very specific kind of OC, with an oddly debated definition. A “Mary Sue” is generally female, and can be characterized by being perfect in every way, even in their imperfections (for instance being an anxious character that is somehow still perfectly comfortable making quick quips or heroic speeches). Everyone in the story loves this character unconditionally, regardless of their behavior. These are characters that are seen as unrealistic in the extreme and are created as wish-fulfillment for the author or artist. They’re a controversial stereotype in fan media.
Gary Stu — The male version of a Mary Sue, who is usually typically masculine and, again, perfect in every way. These characters differ depending on the writer (usually on whether the writer is male or female themselves), but can be anything from a woman’s version of the ideal man archetype (sensitive but strong, that kind of thing) to a full-on macho-man Terminator that everyone still somehow loves.
Ship — An abbreviation of “relationship” which means exactly what it says on the tin. A ship is a pairing of characters. It’s usually romantic, but can be used in a platonic or familial sense.
OTP — “One True Pair.” This is the ship that a fan is particularly fond of, that they think works very well together. This one has a couple of offshoots.
No-TP — This is the exact opposite of an OTP, meaning it’s a ship that a fan particularly dislikes.
Bro-TP — This is a platonic pairing of characters the fan thinks make (or would make) excellent friends.
Reader x — This comes from the categorization style of “Character x Character,” which is used to indicate a pairing. So, “Reader x Character” means that the writer or artist is pairing the reader of the story with a character from the source media, or with another OC in the source world. These stories are a bit unusual in that they’re frequently written in the underused second-person perspective so that the reader is directly addressed by the narrative.
Smut — If you’re unfamiliar with this term, you probably haven’t been on many fandom-dominated spaces. This term refers to writing and art that are…explicit. They may also be referred to as an “R-rated” or “Adult” piece. I really hope you get what I’m going for here so I don’t have to write that out.
Lemon — This is an out-of-date term originally used in the early days of fandom to refer to smut fiction and art. If you remember this term, you’re officially a fandom veteran.
Congratulations, you have the terminology down!
Of course, this isn’t all of the unique terminology used by this subculture, but it should be enough to help you understand fandom conversations when they come up. It’s fascinating to look at the very specific terminology that comes up when discussing fandom and fan media. It gives us an insight into what has become important enough to be universally named and recognized as a staple of the subculture.
And it really is a subculture all on its own; it’s got its own identifying features that set it apart from mainstream popularity and subdivides into hundreds of thousands of categories based on the actual media the fandom grows up around. Yes, fandoms can be a little silly and childish, and they can definitely cause serious trouble, but it’s because of them that media is continuing to evolve to be more inclusive, interactive, and dynamic, relying on their feedback to innovate and change what we consume and how we do it, which is pretty cool, if you ask me.