AMV (Animated Music Video)- A video with clips or Fanart in it with accompanied music fitting to  the subject

AU (Alternate Universe)- A story of an existing show/book/game that has story line slightly altered from the cannon, usually in the form of a fanfiction

Avatar- Something representing someone on the internet; A game sprite, usually pixelated

Bash- insult something for the sake of insulting it

Beta Reader- a fanfiction editor; Someone who goes over a fanfiction to find grammar mistakes for the author before they publish it

BNF (Big-Name Fan)- Someone very popular in the fandom

Canon- Something that happed in the actual show/book/game

Chibi- Fanart where characters with large head and eyes, and small, chubby bodies and limbs, as if they were toddlers

Claims-  a site or page on a site where individuals can entitle, or "claim,"ojects from the cannon, such as an outfit or hairstyle

Con- Short for Convention, like ComicCon

ConCrit (Constructive Criticism)- helpful advise given to an author of a story from a reader

Cosplay- dressing up as a character from a fandom

Crosscast- Fanart or fanfiction that has the same plot as the cannon, but uses the character of another cannon

Crossover- Fanart or fanfiction that has plot and/or characters from two different cannons meet

Dead/ded- a term used by fanboy/fangirl when they hear/read something funny, surprising, or appalling

DLDR (Don't like, Don't read)- A term authors use as an answer to bashes and sometimes  ConCrit.

Dreamcast- a list of actors/actresses that a fan would hire if the form of media their fandom is was a movie

Dub- a rerecording of an animation where the language used is rerecorded in a different language

Ebert's Law- a rule stating that one does not have to be at something to see when someone's bad at it

Eyesporking- a term used to describe a terrible fanfiction; Eyesporkingly bad

Fanart- a drawing depicting something or someone from a fandom, whether it is from canon, fanon, or OC

Fanboy- A seriously obsessive fan who is male

Fandom- a community dedicated to a work, such as music, animation, book, or game

Fanfiction- a story about the fandom that is noncanon

Fangirl- A seriously obsessive fan who is female

Fanon- something that is noncanon, but is generally used in the fan community that people who don't know the fandom or are new to the fandom may think it's canon; examples: Eridan saying 'nweh!' a lot when he never said it in Homestuck, or the Sockathon ship in Welcome to Hell

Fanpoodle- a more intense fangirl

Fansubs- a form of media in which people within the fandom have put subtitle for different languages in so others may enjoy it as well

Fanzine- a collection of fanfictions and fun facts from a fandom put together in the form of a magazine

FAQ (frequently asked question)-  a question asked by most fans, with pages answering them

Filk- a song parody

Filler- an episode of a show that fills time, but contribute nothing to the main story

Flame- insults to a fan's work or the act of insulting said object

Fluff- a fanfiction that does not have much plot, but doesn't deal with dark topics either; a fanfic. that has cute love scenes in which the to are the two characters in love with each other interact by flirting and other small signs of affection

GIP (Gratuitous Icon Post)- A post in an online conversation in which someone shows that their icon or sprite is related to the subject

Gush- to say only good things about something in precise detail, stating everything one loves about something.

HSAU (High School AU)- An au where all the characters are students who go to high school together

Hurt/comfort- a fic. in which a character is abused mental/physically, and helped back to happiness by a close friend or their true love

IAWTC- I agree with that comment

IC (in character)- used to point out that a character in a role-play or fanfiction is acting the same as they would normally behave

IMHO- In my humble opinion

leet (Eleet)- used for people who are exceptional at leetspeak

leetspeak- a method of typing that is hard to read but is still comprehendible if the reader really tries; |-|!

Lurker- someone who watches a message board or chat room without contributing to it, often to know how to behave before introducing themselves, or to learn more about the subject

MarySue/GarrySue- an OC or the like which is overly explained, and beautiful, perfect and likable in everyway from the authors point of view; an OC with lots of beauty and power, with no weaknesses or flaws

Meme- a small picture with text around it stating a joke; a short video that's considered humorous and has audio and video come from two different things that look good together

Mod (moderator)- The person in charge of an archive, website, blog, page, or chatroom

Netspeak- using an excessive amount of shorthands and abbreviations in a chatroom or text

Newbie- Someone new to a game or community

Notbot- Someone who excessively flames, trolls, and bashes a person out of extreme hate for the individual or something they did/do

OOC (out of character)- Used to refer to when a character in a fanfiction or role-play is acting differently from what they normally would

OP (Original Poster)- a person who originally started a discussion/chatroom

OT (off topic)-used to make a post that you want to sent out to someone, but is unrelated to the conversation at hand

Otaku- a person totally obsessed with anime

OTP (one true pairing)- The choice of a pairing one thinks would be the only pairing out of a certain thing/all their pairings; One's favorite pairing out of a set of pairings

Pairing- two characters together in a romantic relationship; a ship

Pic- picture

R&R- read and review

Round Robin- a fanfiction that has many authors

RP- Role-play

Ship (Relationship)- a pairing

Shrine- a website/page where a work/character from said work are depicted, so fan can tell others that they like something

Snuff- a fanfiction that exists solely for the purpose of the author killing off a character they hate

Sockpuppet- Someone who has a negative opinion on something, and posts their opinion under multiple different accounts pretending to be different people to prove their point

Songfic- a fanfiction where the plot is based of off a song

Sub (subtitles)- A show that has the original dub, but has the words in a different language at the bottom

Suethor- An author that writes many MarySues

Thread- all the replies and, replies to said replies, to a statement online

TL;DR- Too long; Didn't read

Wingfic- a fanfiction where all the characters have angel wings

For moar, go on Ainself.net, where I got most of my information.  They have other words that I didn't put on here for various reasons.  Enjoy, and happy reading!