aggro radius

Used commonly in MMORPG games such as World of Warcraft, Everquest, etc. to describe the area around a single player, a group or a raid within which a mob will aggro and attack the player or players. The aggro radius varies depending on the levels of both the player and the mob. The higher the player's level, the smaller the aggro radius of the mob, meaning the mob will be much less likely to attack the player.

As a player, your aggro radius is something you're constantly aware of when moving through a zone or area full of mobs, especially those zones of the same or a much higher level than yourself. You have to be watch your aggro radius during a raid, for the benefit of the whole raid. Woe betide anyone pulling additional mobs during a raid because they weren't watching their aggro radius. Your Raid Leader will hate you.

The term aggro radius can also be used outside of the gamer world - irl - to describe your general personal space and the annoying tendency of some people to wander into it and piss you off, which can occasionally result in a similar outcome of blood, guts and mayhem.

Crap, this zone is, like, 20 levels higher than me... I'm watching my aggro radius like a hawk. I'm gonna get ganked any minute and wind up taking a dirt nap.

Raid Leader: "Watch your aggro radius, people."

Duuuuuuuudeeeeee, you moved us right near those elites and stuck them in our aggro radius...now we've got a huge corpse run arrrgghhhh!!!!111!!!!!!!!!.

This eejit is really getting in my aggro radius. It's gonna get messy if they don't back off soon.