How to understand the “Availability” of the CAP theorem?

Question

I don\'t know if this is a proper question here.

As we know, in the CAP theorem, \"A\" means \"Availability\". On wikipedia, the explanation of \"Availability\" is:

Answer 1

I agree with Mark Burgess: The CAP Theorem Is Not a Theorem. The CAP properties in the conjecture by Brewer are simply not well-defined enough to provide a rigorous mathematical proof. So, the reason availability is hard to "understand" could be because it is simply not well-defined in this context.