I/O 

It means Input/Output.

A word in the computer person's dictionary.

I/O by Keael July 3, 2005

I/O 

When referencing a pet, this term stands for Indoor/Outdoor.
That is, a dog or cat that spends as much time outside as it spends inside.

Candy is our new I/O cat -- she sleeps outside at night but comes in the house to play with our other kitties during the day.

I/O by Telephony May 1, 2015

i_o 

An American DJ/Producer named Garrett Falls Lockhart aka i_o meaning infinitely_one who’s legacy will live on.

Rest in Ether 🖤 05/17/1990 - 11/23/2020

1. Dude I miss i_o so much.
2. i_o is such a talented producer & dj!
3. Have you heard ‘Bad Things’ by i_o & No Mana?

i_o by Peace & love <3 January 13, 2021

I/O shield blood sacrifice 

A term used when building a computer, specifically when Installing the I/O shield, and cutting yourself, as they are notorious for being sharp.

Ex. of the "I/O shield blood sacrifice"

Man: I was about to throw the whole tower against the wall! I felt like such an idiot. The IO shield is evil and requires a blood sacrifice!

Friend: It really is. I did a case transplant on Friday and it took blood even just for being moved from one case to another.

I/O shield blood sacrifice by TheNightAngel June 5, 2013

I O U 

Short for "I Owe you".

"I O U 20 bucks
-signed Bob"

I O U by MKahy May 22, 2008

i_o_i 

It's good. emoticon resembling a football referees symbol for a made kick.

"yo, you see that girl last night? .... i_o_i"

i_o_i by actinafoo June 19, 2007

i.o.u. 

I Owe You

i.o.u. by cool guy August 13, 2003