'Why use the words non-duality?' Listener question

Would you be able to say a bit more about the reason why "Non Duality" speaks to Wholeness, more than the word "wholeness" does?  (ref your first video on Wholeness in Home).  For me wholeness is the whole, there isn't anything outside that.  If there's an implication, inherent in the word "whole", that there is something else that is not whole,  then why isn't that also true for the word Non Duality - which points to the state of the very absence of non-duality very clearly.  Simply because of the prefix Non" and the word "dual". 

I know we're using words and concepts to describe something beyond the intellectually understandable.  Yet the use of Non-Duality to describe what we're exploring in this conversation doesn't really settle into my mind - it always somehow makes it seem cerebral and distant when we're talking about something so very very intimate to every moment experience.