Time to Live
Time to Live (sometimes referred to as TTL) is a metric used to quantify a player's survivability assuming no healing is performed (either self-healing or from other Team members).
Traditionally, this is a metric highly valued by Tanks (a Tank is a player whose role in a group scenario is to take large amounts of damage and hold the enemy on him, protecting the damage dealers in his party, so that they can get on with their job, i.e. doing damage) and directly refers to the length of time required to kill a player given an anticipated stream of steady incoming damage without any healing. In its most simplistic example, imagine a player character with 100 hit points, taking damage at a rate of 10 damage per second. Excluding any bonuses or damage reduction, that player's time to live is obviously 10 seconds.