Definitions for "Ability drain"
A permanent loss of 1 or more ability score points. The character can only regain these points through magical means. A character with Strenth 0 falls to the ground and is helpless. A character with Dexterity 0 is paralyzed. A character with Constitution 0 is dead. A character with Intelligence, Wisdom, or Charisma 0 is unconscious. (D&D 3.5)