An expression of approval and/or indicator of future action. As popularized by Lil' John.
"We gon' get up in dis party tonight! Y'all ready? Lemme hear you say 'OKAAAAAAAAAAAAY!'"
Word commonly used by famous rapper/artist Lil Jon. Has no meaning what so ever..he just says it, thats the only reason he makes money.
White Guy- Hey Lil Jon, want to go hang at this bangin party?
Lil Jon- OKAAAAAAAAY!