WoW Terminology

Tradeskills
LW = Leatherworking
BS = Blacksmithing
Mats = Materials required for creating an item

Zones/Cities
TN = Thousand Needles
TB = Thunder Bluff
STV = Stranglethorn Vale
Org = Orgrimmar
UC = Undercity
BB = Booty Bay
SoS = Swamp of Sorrows
TM = Tarren Mill
XR = Crossroads
Mulg = Mulgore

Instances
BFD = Blackfathom Depths (Ashenvale)
RFC = Ragefire Chasm (Orgrimmar)
SM = Scarlet Monastery (Tirisfall Glades)
Uld = Uldaman (Bad Lands)
WC = Wailing Caverns (Barrens)
ZF = Zul'Farrak (Tanaris)
Mar = Maraudon (Desolace)
SFK = Shadowfang Keep ()
BRD = Blackrock Depths ()
BRS = Blackrock Spire ()
RFK = Razorfen Kraul (Barrens)
RFD = Razorfen Downs (Barrens)


Combat
OOM = Out of Mana
Pat(s) = patrol(s) incoming
Mez/Mes = mezmerize (a Warlock's Succubus's crowd control skill)
Sheep = to turn a mob into a sheep. Can also be used, "I've been sheeped."
Frogged = "I've been turned into a frog"
Ribbit = a variation on the above
Mob = any npc monster
Add = another mob has started attacking us
Adds = 2 or more new mobs have started attacking us
DPS = damage per second. Can be used in a variety of contexts such as, "We need more dps." (Our party needs to deal more damage, let's find a mage or a rogue.) "What's your dps?" (What does your character page or Cosmos report your dps output to be?) "We're not doing enough dps." (Fights are taking our party so long to complete that our healer is runing out of mana before we're finished, and we're in constant danger of wiping.)
DOT = Damage Over Time (any skill/spell that continues to do damage over a period of time after it has been used. i.e. Shammy's Flame Shock or Rogue's weapon poison.)
Wipe = when a whole party is killed
Crowd Control = any method of reducing the number of mobs being fought at once (i.e. Mesmerize, Polymorph)
Crit = a critical hit dealing extra damage
Kite = lead a mob to a new location
Pull = to attract a mob to you so you can fight it
Body Pull = rather than using a ranged attack, pulling by running up to a mob and kiting it back to your party
Inc = Incoming (usually used to alert other players you are pulling a mob)
Leash = when a mob stops attacking you and runs back to it's home location
PK = Player Killing (usually negative context. Compare to PvP)
Repop = when a mob respawns after having been killed
Rez/Res = Resurrect
Root = stop a mob from moving who is still in combat (i.e. Mage's Frost Nova, Druid's Roots)
Runner = a mob that becomes feared when it is close to dying and runs away. Usually humanoids
Nuke = when a mage attacks without cosideration for building hate, and attempts to take down a mob as quickly as possible by using it's most powerful spells. Specifically used with mages due to the massive amounts of damage they can deal.
FMB = Full Mana Burn; attacking w/o consideration for mana conservation and focusing on bringing down a mob as fast as possible

Misc.
AH = Auction House
Grats/Gratz = Congratulations!
Punch & Pie for [playername] = (see grats)
FP = Flight Path
AC = Armor Class
AFAIK = as far as I know
BRT = Be Right There
OMW = On My Way
GG = Good Group or Good Going
GL = Good Luck
GJ = Good Job
PvP = Player vs. Player
PvE = Player vs. Environment
RP = Role Play
Grief = unfairly disrupt another's play, usually via PvP
HP = Hit Points
GTG = Got to go
J/K = Just Kidding
LFM = Looking for Member/More (a small group wants more members)
LFG = Looking for Group
Ninja = Unfairly looting corpses/items before others have a chance. Not sharing looted items you don't need
NP = No Problem
NPC = Non-Player Character
PST = Please Send Tell (send me a private message/whisper)
Greed Roll = Rolling to determin who gets to sell an item once everyone has passed based on need
Str = Strenght
Agi = Agility
Int = Intellect
Sta = Stamina
Spi = Spirit
WTS = Want to Sell
WTB = Want to Buy