here, lets start over with the part you avoid: what is a mind, the mind, and minds?
Would a definition help?
the element of a person that enables them to be aware of the world and their experiences, to * think, and to feel; the faculty of consciousness and thought.
I would suggest that that definition is fairly good, although I'd add the word consciously where I've inserted a *, to distinguish conscious from unconscious activity.
If you're after something a bit more academic, you could go with something more akin to Theory of Mind.
https://www.google.co.uk/#q=Theory+of+mind
You seem to have a certain degree of scepticism that discussion is even possible, despite this being a popular topic for the last few hundred years. Can you share what you're trying to get at with your demands for definitions?