when you knock on the door a certain way so they know its not the cops. the knock sounds like: dun,da,dun,dun(fast) DUN, DUN (slow). it was originially a theme song for a super hero i think. it's got a nice rhythm to it though.
I don't think people really call it the ghetto knock, they just do it out of habit.
av caitlin 1 mars 2005