Terms here are going to be associated with WoW specifically or with gaming in general.
- CD - Cool Down. When a non-instant spell is on a recharge, its said to be on a 'cool down'.
- Dev - Developer. Most specificly the gam or class developers at the software company working on the game.
- DPS - Damage Per Second. How much damage per second your character does when fighting.
- DR - Diminishing Returns. Some spells or effects become less effective on a player [in PvP obviously] the more you use it(them). Usually these fall under the categories of Fears, Snares, Traps, Stuns and Crowd Controls [basicly anything the affects movement and/or control of your character]. (ie- "I can't believe Fear has been added to the DR list! Lame :(")
- MMO - [MMORPG] : Massively Multi-player Online Roleplaying Game. If someone talks about playing an MMO, that's what WoW and City of Heroes, etc. are. Games where large amounts of players (more than 64, the standard max for most FPS Mult-player games [ie Unreal Tournament, etc.]) get together and play in a persistant and ever-changing gaming verse.
- Nerf - This (I've been told) is a reference to the 'Nerf' line of toys that shoot foam darts and are therefore safe and unthreatening or cause little damage. In game it refers to the Devs 'Nerfing' a class or spell to make it(them) more ineffective (less overpowered), by the gamers that use or play those classes and spells. "Gawd, the Devs really nerfed us Pallies!"
- OP - Overpowered. The cry of other classes or specs that states 'X' spell of class is overpowered and therefore MUST need nerfing.
- RPG - Roleplaying Game. WoW or D&D, etc.
- RNG - Random Number Generator/Generation. Think of this like the old dice games, like DnD. You roll 'x' dice to see if your spell/melee attack hits. Every now and again, even a Epic geared Warrior gets screwed on a roll, and misses the guy in open daylight at pointblank range. Sometimes the fates are just aligned against you.