Uncle DaveO, I'm always hoping to meet someone who is at a higher level of understanding (about anything at all) than I am...and I do meet such people. If I met Mark Knopfler, for example, I believe he would be at a much higher level of understanding about guitar playing than I am, and I would pay close attention to anything he could show me.

If you want an airtight definition of "higher level of understanding" that will automatically identify it at ALL possible levels, I can't provide it. I'm not at at high enough level of understanding myself to be capable of that. ;-)

Just find your own definition of the concept and I'm sure it will work for you.