Aggro Radius

Aggression Radius
Common gamer lingo for the distance at which a mob "notices" you and decides to attack you. For most games, this is a constant, but occasionally you will encounter a mob with a much larger "Aggro Radius" than normal, and this is worth knowing.
Likewise, most Boss mobs have a very small "Aggro Radius" and must be within melee range (50?) before they get angry.
Naturally, if you attack a mob from outside his "aggro radius", he will get angry immediately.
See also: Hate