Kiyosaki had a definition I liked. (Love him or hate him!) It was that being wealthy meant you could cover all of your expenses with income from your assets. This mean that you simply had positive free cash flow now and forever if you lived at your current means or below.
The great thing about this definition is that it is all relative. It takes into account what money is really meant to provide, a means to an end. If you have enough means to meet your ends, and you don’t have to work to do it…that is wealthy!