Adds: Refers to enemies that spawn or wander by during fights.
AoE: Area of Effect, a talent or skill that allows multiple targets to get damage simultaneously
Buff: a buff refers to a temporary beneficial spell or effect placed on a player.
Debuff: A debuff is the contrary of a buff. It is an effect that while it persists hampers the target in some way.
CC: Crowd Control, any of various mechanisms used temporarily to limit an enemy's movements or behavior, such as a mage casting polymorph (a.k.a. 'sheeping'), a hunter using ice trap, a priest casting shackle undead, or even a druid using Hibernate.
DD: direct damage, means the people who produce the direct damage, or we call them DDer.
DoT: Damage-Over-Time, usually referring to a spell or ability which harms an enemy over a period of time.
DPS: Damage per second is a measure of the damage dealt by a person or group over one second.
healer:
HoT: Heal over Time. When a skill heals for an amount over a duration of time.
Loot:
MT: Most commonly used for Main Tank when in Raids/Instances. Tank means the
ST: slave tank
OOM: Out of Mana, unable to cast spells.
OT : off tank , that means
RL: raid leader