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13.
AO
a person whose favorite activities include going to the gym, playing tennis, binging/purging, and cruising men's restrooms at UCLA
the guy in the sleeveless pink muscle tee blew AO through the glory hole
by lb627 November 14, 2006
 
1.
AO
Area of Operations. Army-speak.
When the General showed up at the barracks it was time to unass the AO.
by Parnelli Joneser May 07, 2005
 
2.
AO
..is short for ‘Adults Only’ (most extreme videogame rating in the U.S.). See also the other vg ratings: EC(Early Childhood), K-A(Kids to Adults; was replaced by 'E' in 1996), E(Everyone), E10+(Everyone ten years of age or older), T(Teen), M(Mature Audience), AO(Adults Only), and ESRB.
GTA:SA(Grand Theft Auto: San Andreas) is no longer rated 'M', but instead 'AO', and subsequesntly is no longer on the shelves, barely in stock at all.
by Victor Van Styn July 26, 2005
 
3.
AO
..is short for ‘Adults Only’ (most extreme videogame rating in the States). See also: EC, K-A, E, E10+, T, M, AO, and ESRB.
GTA:SA is no longer rated 'M', but instead 'AO', and subsequesntly is no longer on the shelves, barely in stock at all.
by Victor Van Styn July 26, 2005
 
4.
Stands for Accidental Ownage. When someone shows off and fails, or something like that.
Dude, this guy was trying to do a handstand on a rail and he flipped over.
Whoa, that's total A.O.
by Macguire1 August 22, 2008
 
5.
A-O
Often used in celebratory fashion.
Ex1. "Hey its-a-me"
"A-O!!!!!"

Ex2. "Yo dis chick said she would totally give you head"
"AAAAA-OOOOOO!!!!!!!!!!"

by hasselhoffman February 27, 2009
 
6.
ao
MMORPG Anarchy Online
by stevo July 03, 2003
 
7.
AO
A reference to the Bum-Bum, Anus, Ass, Brown-Eye, etc.
Stick that shit up in the AO!
A-OoOoOoOoOoOoO
by Gringey Jam March 05, 2005