Tank
A Tank is a hero (typically a
Strength based one), whose primary role is to absorb large amounts of damage from enemies and draw attention away from allies. To achieve this, they generally have several defensive abilities that grant armor, regeneration, or bonus damage (e.g. Dragon Knight's Dragon's Blood, Centaur Warchief's Great Fortitude, Bristleback's Bristleback, Tidehunter's Kraken Shell), as well as a high Strength gain.
Also, tank can be used as a verb, meaning to absorb large amounts of damage (namely, to tank it).
A tank ideally needs some form of threat or significant damage output in order to draw the enemy fire. It is for this reason that tanks often aquire a radiance, giving the enemy the option of trying to take down the tank, or take the damage.
Given the variety of items in dota, almost any hero can be built as a tank, and having one in the team is advised, there is no point in having a huge damage output if your whole team is already dead.
Common tanking heroes
Common Tanking heroes are the
Bristleback,
Dragon Knight,
Centaur Warchief,
Stone Giant,
Axe,
Tidehunter,
Treant Protector and
Pandaren Brewmaster. All of these heroes possess at least one defensive spell.
Other noticeable tanks
However, certain other heroes are also considered tanks, without necessarily having an ability that increases survivability. Such heroes include the
Axe, whose Counter Helix, while not negating damage, can synergize with Berserker’s Call to deal heavy damage to nearby enemies. Another noticeable Tank was the pre-6.50
Spectre, whose Dispersion ability allowed her to deflect damage to enemies. A hero does not however need to be strength based inorder to tank, Medusa, an agility based hero is capable of tanking using
Mana Shield, which depletes her mana rather than life when she takes damage.