CoA
Curse of Agony, a warlock spell that does damage over time. It ticks for more at the end of its duration than at the beginning.
CC
Crowd control. Any spell or ability which incapacitates the target for a certain amount of time, stopping it from harming the player or his party. Also refers to any class with such an ability.
Caster
A character that stays at a distance to heal allies or cast offensive spells on the enemy
Buff
A beneficial spell cast on a monster or player.
BRT
Be Right There
BRD
Blackrock Depths, an instance underneath Blackrock Mountain between Searing Gorge and Burning Steppes.
Bot
The Botanica, a Tempest Keep instance in Netherstorm
BoP
Bind on Pickup. A BoP cannot be traded once it is looted or created
BoE
Bind on Equip, BoEs can be traded until they are equipped by a player
BM
Black Morass, a Caverns of Time instance in Tanaris. Also, Beast Mastery, a Hunter talent tree.