@Owen phil,
Unfortunately people often confuse the concept with the thing to which the concept refers...in the case it gets even worse since the concept when rationalized by its own definition does not refer to anything...Understandably it must n´t, once it clearly states
no-thing.
Now the question further develops on trying to understand how can a concept not refer if all concepts must refer...how can the trick be done in the mind ?
In the case is my opinion that this "No-Thing" by abstraction refers to that which was never seen, never eared, never thought...to no memory !
Therefore by that which is sort of "designed" on the surrounded void created by all that is and can be conceptualized of...
...and such, goes and goes gradually on the mind, in a process that working like a shadow is drawn and chasten by the entirety of those things, that we can think of at any moment as laying around that very same nothingness, thus slowly, starting to bring "to life", the illusory projection of an emptiness with shape...
...As I said, a mistake in the mind, and for the mind if one does n´t mind...