UO UO 

in World of Warcaft, a funny way for Horde players to annoy scare Alliance players.
Because of the language mess-up system in WoW, if a Horde player says "UO UO", any Alliance player who hears it will see "HA HA" instead. most of Allys run away seeing that, thinking they've met a GM's alt who has cross-faction communication. "UO UO" can be extended, so if you prefer "HA HA HA" over "HA HA", there's no problem!

try it out!

Horde player: *kills an alliance player* UO UO

Other alliance player to alliance player: omg this guy can write to us normally O.o i better run away hes a gm or something cya *bubble hearth*

UO UO by vtf_sandvich March 7, 2009

Uo 

When a person mistypes “up” on a phone.

Guy 1 on phone: Have you watched Uo recently?
Guy 2 on phone: did you say Up?
Guy 2: SHIT

Uo by ion0320 November 2, 2018

UO 

Unpopular Opinion. When you express an opinion that is completely against what most people say.

UO: I think Rebecca Black is amazing.

UO by BlaineW October 1, 2011

UO 

Short for Ultima Online, a game released in late 1997. This was the "first" successful MMORPG (Yes technically there were others but none on the scale of UO). It was possibly one of the most unique and immersive games in the market at its peak (98-01). The game was quickly massacred and mutilated beyond recognition with nerfs/cheesy neon graphics after the release of its third expansion.

I used to play UO for the PvP... now I'm waiting for WoW

UO by Azaroth March 26, 2004

UO 

The University of Oregon, located in Eugene, OR. Often confused with OU (University of Oklahoma), another high caliber university. UO has a solid reputation as one of the top flagship universities on the West Coast. A member of the AAU (Association of American Universities) that consists of 62 best public and private universities in terms of research and education. UO's athletic teams, the Ducks, compete in the Pacific 10 conference.

UO is a fine university that combines excellent academics with an elite athletic program.

UO by Michael.Bennett September 22, 2007

Pro UO 

Refers to those in the game Ultima Online.

People who devote ample amounts of time to improve their skill in the game, and take it seriously than most others.

We just got owned again. Those guys are Pro UO.

Pro UO by Blot May 8, 2007

UO 

Short for Ultima Online. It is overall a very interesting game that has been around for five, nearing six, years. In essence, it is a drug.

"Sorry Honey, can't come to bed yet, I'm busy playing UO."

UO by Lonegamer May 23, 2003