In-game lingo: these will be used in chatting/forums, for the most part.
WoW: World Of Warcraft
TBC: The Burning Crusade, The expansion released January 14th 2007 for the World Of Warcraft.
Mats: Short for Materials, generally used in crafting professions.
Prof: Professions, can be split into three groups:
Crafting Prof.: Build your own gear from materials you gather around the World Of Warcraft, They are: Tailoring (Tailor), Blacksmithing (B.s.), Leatherworking (L.w.), Alchemist (Alch), Engineering (Eng), JewelCrafting (Jwl) and to some degree Enchanter (chant/Ench). The maximum level of these professions are level 375 with The Burning Crusade, lvl 300 with Standard WoW.
Gathering Prof: Professions that supply mats for the crafting professions, They are: Mining (for blacksmithing and engineering), Herbalism (for Alchemy), and Skinning (for Leatherworking).
Second professions: These are professions that don't require one of your two profession slots (you can learn all three of these, and 2 main professions) Fishing, Cooking, First-Aid.
FTLFor the loss, guess what, we just lost.
FTWFor the win (d), victory.
LFG: Looking For Group, used when someone is looking for someone else to party with, generally for an instance, or quest.
LFM: Looking For More, used when a group is looking for more people to do an instance or quest, generally a class title and number follow this Ex: (LFM 1 Priest, and 1 Rogue)
PST: stands for Please Send Tell, meaing you want to hear back from someone who is interested.
Req: Requirment, Pre-requisite. Something that needs to be done before something else happens, (must be level 20 to wear X equipment, must have X in invintory to begin quest)
Newb: (Noob, Nub, Nublet, Nubile (oops!), Noobie) Someone without experiance in the game, most people start out with this status, given by other players.
Rep: reputation, when killing certain creature, or doing certain quests, The rewards sometimes include reputation with certain factions in the game, these can lead to cheaper product buying, and even some special items only available to people who put in the time to gain the required reputation.
QFT: Quoted for truth in my terms. other people will toss it out as quite friggin true (or other F-expletives)
B.G.: Battleground: an area designated for the killing of the opposite faction, Can be entered from any of the major cities. three major pre-Burning crusade b.g.s are Warsong Gulch (WSG, a capture the flag style game 10 player/team limit). Arathi Basin (A.B. Capture and hold nodes to win the game, 15 player/team limit) Alterac Valley (A.V. the largest PvP battleground, kill the enemies general to be victorious, 40 players/team)
Woot: originally We Owned the Other Team (from what ive heard), now its shouted upon success of any endeavors.
IMO/IMHO: in my opinion/in my honest opinion. well, imo you should understand by now.
WT:B/S/T: Want to buy/sell/trade, trade offers generally start with this in the in-game trade channel.
Roll/Reroll/Rickrolled: Roll is another term for the creation of a character, what race/class they are, Re-Roll is to make another character, generally out of dissatisfaction of the first selection. Rickrolled is no satisfaction at all.

Location Terminology:
Cities:
Alliance:
S.W.: StormWind, The human race's main city (connected underground to Ironforge)
I.F.: Iron Forge, the main alliance city for most servers,
Dar: Darnassus, The Nightelf starting city, by far the most alienated of the alliance controlled starting areas.
Exo: Exodar, Drenai starting city, assuming the only city alliance can learn jewelcrafting, i know nothing about this city.

Horde:
Org: Orgrimaar, the central horde city, orcs and trolls start closest to here.
U.C.: Undercity, a city, literaly built under the ground, beneath the ruins of an old castle, elevators take you to the main city, very easy layout, Undead start here.
T.B.: Thunderbluff, opposite of the Undercity, this city is on a bluff, which you have to take elevators up to.
SC: SIlvermoon City, Blood elf starting city, only place in the mainland that the horde can learn Jewelcrafting

[Part 2]

Add = Additional mob. A mob that joins the fight (for whatever reason) while already fighting the initial mob
Aggro = Who the mob is attacking has the mobs "Aggro" this is can only be seen by either having a mod that shows an "Agro list" or, by looking at who the mob has targeted.
AFK = Away from Keyboard
AH = Auction House, a place to auction off the goods youve found on your questing. also a good place to pick up upgrades for your gear.
AOE = Area of Effect (spells that affect multiple mobs within an area) Certain weapons/armor/items can also have an AOE effect - this is important to note because AOE damage will break crowd controlled mobs
CC= Crowd Control, any enemy that isnt able to function is under Crowd Control, this can be anything from a mages sheep, to a priests mind control, or a rogues sap, allmost every class (except shammy) have some form of mind control
Clothie/Squishie: nick-name given to cloth wearing classes, they generally do not have the damage surpression given by higher armor wearing classes.
DOT = Damage over Time, any cast spell that cause X amount of damage every Y seconds.
DPS: Damage Per Second, used to describe certain classes of the game, specificly classes with high damage outputs, Rogues, Mages, Warlocks and hunters are the main four.
Emote= Emotion, more info found here http://www.worldofwarcraft.com/info/basics/emotes.html or make your own using /em !
FFA= free-for-all, looting system in which everyone gets a roll, they can roll
need= A roll that only competes against other need rolls. Represented by a pair of dice on the roll bar.
greed= A roll that competes below need rolls, generally rolled for the purposes of selling. represented by a Gold coin on the roll bar
GD=good duel, said as a courtesy after a duel is finished.
HK = Honorable Kill, when you kill a player of the opposite faction who is within 10 levels of you, you get an Honorable Kill, which can be put towards buying weapons.
HOT = Heal over Time, like a Damage over time (DOT) only X=health recovered.
ML=master looter, allows one person to control who rare item drops go to, only allow your group leader to select this if you really trust them.
Mob: A creature/humanoid NPC
OOM = Out Of Mana an easy way to show that a caster is running out of mana, an Emote is /oom
Pat = Patrol, a Mob, generally in an instance, that "Patrols" a certain area.
PUG = Pickup Group, any group that consists of people you have no relation to, and are therefore, Picked up.
PVE = Player vs Environment, this broad term is defined by any Player (you) interacting with any Non-player.
PVP = Player vs Player, Any player interacting with any other player, usually through COMBAT!
Ninja = A player who takes loot to which he or she is not entitled. being a ninja is not a good thing.
Pull = The act singling out a single enemy from a group of mobs. When that enemy is a safe distance from the rest of the group, it can be attacked and killed without aggroing the others.
Proc = activation of a chance ability/spell/etc. "That enchant only procs 2% of the time" meaning the enchant's effect is seen in 2 out of 100 of the events that could make it activate (swings, hits, whatever).
Tank: The main damage taker of a party, his job is to keep enemies off of other members of the party.
Trash Mob:A Mob in an instance impeding your way to the Boss Mob.
Pot: Potion, used for quick recovery of Mana or health. Can be made by Alchemist.
Twink: someone who reaches a certain level, and doesn't intend on leveling any more, Generally the top level of an instance set, 19, 29, 39. They mostly try to get the best items they can for their level, the most expensive enchants, merely for winning battlegrounds.
XP: Experiance, Gained after turning in a quest, or killing a Mob.



Instance: a "course" pre-laid out for a party to do, sprinkled with "boss" mobs, and events, generally have their own story line behind them, and they mostly all have their own nick-name. I only have enough space to explain the lower level ones, I hope you get the drift before you reach level 40 smile.gif :
RFC: Rage-Fire Chasm, a lvl 12-17 instance set in the midle of Orgrimaar, 3 major bosses.
VC: An odd nickname at first, it stands for Deadmines, a place in westfall, with the endboss being a man known as VanCleef. (hence the nickname) DM is another instance that you will get to later on.
Stock:Stockades, Alliance "only" instance requiring lvls 20-26, found in the southwest of stormwind, 3 wings, 3 bosses. (from what i remember)
WC: Wailing Caverns, probably the longest low level instance, lvl 18-24, found in The Barrens, as accesible to the alliance as VC is to the horde.
SFK: Shadowfang Keep lvl 22-28, found in southwestern Silverpine Forest, this instance along with VC have arguably 2 of the best storylines to them in regular WoW
BFD: Black Fathom Deep, lvl 22-28, found in ashenvale. all i know.
Gnomer: Gnomeregan, lvl 28-34 instance, found south of IronForge. And Fabrizia's Favorite
RFK: Razorfen Kraul 28-34, found in the south west (not south east) barrens.
SM:Scarlet Monestary, this instance is divided into four seperate wings, ranging in level from 32 to 46, From lowest to highest, GY: Graveyard, Lib: Library (need to get the key out of here to progress to the next to), Arm: Armory (higher level trash, easier boss), Cath (lower level trash, 2 higher level bosses).

RFK: razorfen kraul (the barrens)
RFC: ragefire chasm (orgrimmar)
RFD: razorfen downs (the barrens)
BRD: blackrock depths (burning steppes)
BFD: blackfathom depths (deeps?) (ashenvale)