Solo
Play alone, without any help from others
SP
Slave Pens, a Coilfang Reservoir instance in Zangarmarsh. Also, Shadow Priest. Also, Sunwell Plateau, a Level 70 25-man raid instance on the Isle of Quel'Danas
Spec
The allocation of talent points which determines how effective a character is at different roles
SPI
Spirit, a base statistic
SS
Southshore. Also Soul Stone, a warlock's conjured item which allows a player to resurrect himself after he dies. Also Stormstrike, an Enhancement Shaman attack that causes the target to be vulnerable to nature damage.
SSC
Serpentshrine Cavern, the Level 70 25-man raid instance of Coilfang Reservoir in Zangarmarsh
ST
Sunken Temple, also known as the Temple of Atal'Hakkar, an instance in Swamp of Sorrows
Stack
A number of identical items placed in a single bag slot, to conserve space. Only some items can be stacked. Also refers to multiple applications of a debuff or buff that increases its effects.
Stam
Stamina, a base statistic
Stocks
The Stockade, an instance in Stormwind
Str
Strength, a base statistic
Strat
Stratholme, an instance in Eastern Plaguelands
STV
Stranglethorn Vale, a zone in the Eastern Kingdoms
Succ
Succubus, a DPS/CC pet used by warlocks. Can seduce, charming an enemy.
SV
The Steamvault, a Coilfang Reservoir instance in Zangarmarsh
SW
Stormwind, home of the Humans
Tank
A character that is meant to hold the attention of the enemy while taking relatively little damage.
Tap
To do damage to a monster, claiming it. Once you have damaged the monster, you are the only one able to get experience and loot from it. Also refers to Warlocks' ability Life Tap, which reduces health in return for Mana.
Taunt
An ability that allows a player, usually a tank, to pull the attention of a monster off of another player and onto himself