1)made popular by the rapper Lil' John in Usher's video Yeah. When someone yells out what as if immitatin Lil' John, just yell out ok in response.
2) most adequate answer to the question what.
3) used with what and yeah.
Bob: So we chiling right?
Jeff: What!
Bob: uh?
Jeff: What!
Bob: Ok!
everything is gravy. I understand it to originate from a newspaper editor who would write it down meaning all correct, but being a newspaper editor he liked to point out spelling errors and would write "orwl korrect" (or something like that!) which got abbreviated to O.K.
A dismissiveword that is used only to confirm the receiving of a message, and does not show any emotion or concern. Often makes people uncomfortable and feel as if they were belittled.