I think literally anything could be used to define "Pokémon Master", and not just according to what fans think Ash sees the coveted title as (you all probably would have figured this out sooner or later). But, since Ash can never seem to win any main series Leagues, it's obvious Ash will never reach his goal in this regard. In fact, he's way short of any fan definition of "Pokémon Master" (and no, I'm trying not to character bash him either, as much as I want him to be replaced as the featured protagonist. This is about as honest of an assessment that I can possibly make of him.)