Chat-Speak for "Oh! Hi There!".

1.Used to greet someone that you haven't seen in a while, or haven't ever met before.

2.Also used when you suddenly notice someone/living thing (greeting).
A.
Bob: OHAIDAR, WHERE HAVE YOU BEEN FRANK?

Frank: WITH YOUR MOTHER. :)

B.
Bob: HEY LOOK! ITS A KITTY-CAT!

Frank: OHAIDAR KITTY-CAT.
by Unusually Vivid July 24, 2009
Get the ohaidar mug.