Table of Contents
RP
Role Play
When one or more people take on the role of a character that is in some way, large or small, different from their real selves, and through those characters act out fantastical adventures. The resulting communal story might be any genre: fantasy, sci-fi, horror, action adventure, romantic comedy...
IC
In Character
When someone is "in" character, they are acting out the ways they believe their character would respond in a given situation. Just like an actor taking on a role, the things that they say and do while following the script may not reflect their own beliefs or personality. Someone who is IC is engaged in writing a communal story. Just because their character is the villain of the story does not mean that the character's player is a villain in real life.
OOC
Out Of Character
When someone is "out" of character, that means they are speaking as themselves and are not pretending to be anyone else. They aren't playing.
RL
Real Life
Lives that people lead when they are being their real, OOC selves. Their OOC selves may like to spend a lot of time RPing, which is indeed part of RL, but not the only part. Also sometimes referred to as "meat space" to reflect that the bulk of what is considered to be "real" occurs away from our favorite glowing picture boxes.
OC
Original Character
This tends to refer to a character that someone has invented entirely on their own, as opposed to a pre-existing character belonging to another author. An example of a non Original Character might be Ash from Pokemon or Gandalf from Lord of the Rings.
NPC
Non Player Character
Taken literally, this refers to any character that is not controlled by a player. In a video game, all of the bad guys, shop keeps and the like that the computer controls would be an NPC.
In RP, this term is used a little less literally, since a player somewhere has to sit down and write the actions of all of these secondary characters. However, if it is not a character that anyone plays as their "main," it probably falls into the category of NPC.
In formally organized RPs, there may be one GM or master Storyteller who is in charge of controlling ALL of the NPCs that appear in a world. In less organized one-on-one RPs, the players might choose to take turns being responsible for describing the actions of the NPCs.
GM
Game Master
Sometimes also called a DM (Dungeon Master) or ST (Story Teller), this is a person who is in charge of the plot and the world in which one or more other people are playing their characters.
The GM describes the events that are taking place, and they describe the outcomes of the player's decisions. In essence, the "character" that a GM is playing is the world itself. This can provide an extremely cohesive, realistic (or thematic) and surprising plot for the other players.
Depending on how the game is organized, they may be the only person authorized to play NPCs and answer questions about the larger world.
OP
Original Poster
Over Powered
This abbreviation has two possible meanings. It either refers to the person who started a particular forum topic, or it refers to a character that has more power or skills than is fair. It is usually easy to tell which one is meant through context.