With an MMORPG (massively-multiplayer online role-playing game), a tank or meatshield refers to a player character capable of taking all or most of the enemy damage. Often the tank is the only class that wears heavy armor, which gives them the most hit points. Pictured is a Worgen warrior in the MMORPG World of Warcraft, equipped with plate armor to better perform his duties as a tank.
Typically the tank or main tank if there is more than one tank player starts the attack to get aggro from the enemy. After the tank has done enough damage other players in the group will assist in killing the enemy. While taking damage all healers are responsible for keeping the tank up (alive).