This is an okay definition but it spreads the definition a little thin as you're conflating Player vs Player (PVP) and Player vs Monster (PVM) tanks. With PVM,

This is an okay definition but it spreads the definition a little thin as you're conflating Player vs Player (PVP) and Player vs Monster (PVM) tanks. With PVM, there is no focus from the monsters directly, they have aggression algorithms, and tanks typically have a way of directly manipulating this (draw aggro). They have skills that improve statistics usually defensive, and sometimes can outright prevent damage with well timed skills. They're "Tanks" because they absorb/prevent damage while keeping attention on themselves. In PVP, Tanks are typically fight starters or stoppers, that is, they come with a skillset that is designed to manipulate the position and movement of other players (often the enemy, sometimes their own), and even sometimes outright incapacitating other players. They are tanks because they have low or 0 damage stun moves, displacement moves (i.e., players are forcibly moved against their will to an disadvantageous position), terrain creation/removal moves (blocks player movement), and typically high health and defensive stats. Tanks in both cases can start fights because they have to pretty much. Their value is not in the damage, but in their ability to set up fights or to absorb damage/attention. For PVP in particular, tanks tend to have very heavy crowd control so you must be careful about if they decide to engage. The .5-2 seconds that is common for crowd control often is "just enough" to remove your main damage dealers from the fight (temporarily or permanently) and then you're at a disadvantage because the team numbers are against you. For PVM, the tank wants to start its skill rotation so it can get specific buffs going and active. ARPGs really don't have tanks btw (mostly RE:Diablo 2). You can certainly build them, but modern diablo forces all players to be damage dealing tanks. Diablo 3 tried to change this a little, but it still just ended up being an "Every stat is perfect" sort of game, and probably with more glass cannon builds.