Big Model: Primarily designed by Ron Edwards of The Forge. A method of contextualizing the role playing game hobby. See this for an explanation.
Dungeons and Dragons: The arch-typical role playing game. See the end of the post for a review of the different iterations of Dungeons and Dragons.
GSL: A Gaming License allowing other companies to produce 4th edition material for the Dungeons & Dragons game. It is generally considered more restrictive than the OGL.
Hot Pizza: A term used to refer to any non-tracked inventory (e.g. quarrels, assorted gear) for mid and high-level adventurers.
House Rules: Often made by gamers for stupid reasons ("more realistic" being the most offensive and common). Usually a bad idea. The best house rules are those that come up during play to help the group focus in play on what a group likes to do.
OGL: A Gaming License allowing other companies to produce material for the Dungeons & Dragons game. Allowed the birth (explosion?) of dozens of new games, systems, and retro-clones. The reason this is so awesome is it allows any content indicated as such to allow such use that is "perpetual, worldwide, royalty-free, and non-exclusive" as long as the license is included.
OSR: The Old School Renaissance. This is not a movement, but rather a term to describe a thing that sort of seems to be happening (am I offending anyone yet?). People like old RPG's, because they are awesome in ways the new ones are not. See A Quick Primer for Old School Gaming.
Retro-clone: A game published that uses the OGL to replicate an older game. A good listing is here, or here. Big names are OSRIC (replicates 1st edition), Swords and Wizardry (replicates 0e), and Labyrinth Lord and Basic Fantasy RPG (replicates Basic D&D Moldvay/Cook). It also includes new games in the old style, such as Legends of the Flame Princess, and Castles and Crusades and the yet to be released Dungeon Crawl Classics Role Playing Game.
RPG: Role playing games. Are you sure you know where you are?
Rule 0: The (unwritten) idea that the first rule of any Role Playing Game is that you can change any rule you wish. A few caveats. If you have to rule 0 a game in order to make it playable, that does not mean that the game isn't broken. Also, if you're going to rule 0 something, let the players know before the game starts. Also referred to as House Rules.
Splatbooks: Small (~100 page) softcover books release en masse to attempt to produce a profit for RPG publishers. The issue is that with a basic book and some dice, you can play for years and never need buy anything again.
SRD: A System Reference Document containing all the rules for basic play of 3rd edition Dungeons and Dragons online for free. Also available for Pathfinder.
Threefold Model: Words used to describe a way of playing that usually make people very angry for inexplicable reasons. Everyone has a bit of each. (Not surprisingly, this matches up to the internal Timmy/Johnny/Spike model of WotC). Supplanted by the Big Model.
- Gamist - A gamer who enjoys systems, manipulation of rules, and tactical play
- Simulationist - A gamer who enjoys rule models of realism, specifics of play and strategic play
- Dramatist - A gamer who enjoys taking a role, acting, and thinking about actions in character.
Iterations of Dungeons and Dragons:
- Chainmail: A wargame with supplimental fantasy rules (1971)
- Dungeons & Dragons: Called 0e, released in 1974, came with three little white books. (1974)
- Basic Dungeons & Dragons: This edition of the game was written by Dr. J. Eric Holmes. One of 2 versions released in 1977, The other version being Advanced Dungeons and Dragons. (1977)
- Advanced Dungeons & Dragons: Hardcover first edition, written by Gary Gygax. The first book released was the Monster Manual Followed by the Players Handbook in 1978, and the Dungeon Masters Guide in 1979. What is referred to as AD&D or 1st editon (1977-79)
- Basic Dungeons & Dragons: A revision of Dungeons & Dragons written by Tom Moldvay (1981)
- Basic Dungeons & Dragons: A revision of Dungeons & Dragons written by Frank Metzer. This was the start of BECMI (Basic, Expert, Companion, Master, and Immortal sets). A hardcover compilation compiled by Aaron Allston was released in 1991. (1983/1991)
- Advanced Dungeons & Dragons 2nd Edition: Called 2nd edition. Mostly compatible with 1st edition. Written by David "Zeb" Cook. Drastically Marked by sales of splatbooks, a large division of many different gaming lines and worlds, and a general decline in sales and attention throughout the 90's. (1989)
- Dungeons & Dragons 3rd Edition: Called 3rd edition (3e). A new edition based around a basic D20 Mechanic. Released core rules for free under the OGL. Published by Wizards of the Coast who purchased TSR. A revised edition (3.5e) was released in 2003. This edition was very financially successful. (2000/2003)
- Dungeons & Dragons 4th Edition: Called 4th Edition (4e). This edition breaks away from many traditional Dungeons and Dragons elements. Uses a more restrictive license called the GSL. It's release was marked by the firing of many key WotC staff, and has nowhere near the success of previous editions of the game. (2008
- Pathfinder: Called 3.75e. Released by Paizo after the end of the 4th edition line. Continues revisions to the 3.x edition of the game. Very successful financially. (2009)
So, did I miss anything?