Daily

A quest that can be repeated once per day. These are usually level 70 and used for making money or gaining reputation with a faction

Darnassus

Darnassus, home of the Night Elves

DD

Direct Damage. This refers to spells or abilities which deal all of their damage on impact, rather than over time.

DE

Disenchant, create enchanting materials from uncommon, rare, or epic items.

Debuff

The opposite of a buff, usually a spell that lowers the target's attributes. Debuffs can sometimes be dispelled by certain spells or abilities.

DM

Dire Maul, an instance in Ferelas. Sometimes means Deadmines, an instance in Westfall

DoT

Damage over time. This refers to spells that cause damages in multiple ticks over a period of time

DPS

Damage Per Second

Durn

Old Hillsbrad Foothills, a Caverns of Time instance in Tanaris. Refers to Durnholde Keep, which you must escape from in the instance.

EotS

Eye of the Storm, a 15-man battleground with four towers for controlling and a flag in the middle for capturing.

Epic

Other than legendary, the rarest and highest quality type of equipment available

Farm

Content that doesn't pose a high amount of challenge. Can refer to many things from gathering materials to repeating a raid encounter that has been defeated many times.

FFA

Free For All, a type of looting where anyone can loot any corpse

FTL

For The Loss, used to express disapproval of a player, ability, strategy, or anything else.

FTW

For The Win, used to express approval of a player, ability, strategy, or anything else.

Gank

A term used when a player kills another player who has little or no chance to win, such as while already engaged in combat.

GCD

Global Cool Down. Activating most abilities or spells causes this to begin, blocking the player from using any spell for between 1 and 1.5 seconds

GM

Game Master. Someone employed by Blizzard Entertainment to assist and help players. Also can mean Guild Master. Also refers to Gold Mine, a node captured in Arathi Basin.

Gnomer

Gnomeregan, an instance in Dun Morogh

Green

Uncommon level items. The lowest quality of items that can be disenchanted and the most common type of enchanted gear. Better than whites or grays, worse than blues and purples.