A fork of Rural Dictionary
Short for "Age of Shadows" - the version of the popular online MMORPG Ultima Online that moved focus more onto what items the player has in his inventory than his actual skill.
Ultima Online: AoS completely took away any skill involved whatsoever in PvP combat.
AO = All Out. Its the hip new slang way of saying All Out. It was made popular when Ethan of HG added it to his vocabulary. And now all the cool kids at school are saying it.
"Dude, that move was f*cking AO!!! You shot them all in their faces."
A reference to the Bum-Bum, Anus, Ass, Brown-Eye, etc.
Stick that shit up in the AO!
A-OoOoOoOoOoOoO