Good questions!!!!This is not spelled out clearly in the literature I have found.  In my experience and speculation there is something about "knowing" that seems to be tainted by consciousness or mental activity.  I think there's a more pure or more separated  knowing and/or knower that is beyond.  I'm not there yet and the Buddhists leave this mystery to be unveiled in direct experience.  

I can only be a parrot in terms of defining the absolute.  These are the Buddhist insights and other terms I am familiar with

1. unchanging
2. free of suffering, unsatisfactoriness and stress
3. no self, substantiality
4. deathless
5. unconditioned
6. unbound