What is Sio?
1.
The term "sio" is a New Zealand innovation for saying "
Pronounced see-oh (quickly)
Chick: See you at the club later tonight?
Dude: Yup. Sio sio.
See
2.
Significant Internet Other.
Refers to somebody with whom you spend a significant amount of time talking to online, but rarely or never see in the real world.
"Steve's my SIO"
"Wow, you spend a lot of time talking to him. Is he your SIO?"
"I had a fight with my SIO and he blocked me."
See