for the whoevers - what does the word "urbanism" awakes in your mind?

There's a big spectrum of associations, connotations, connections, or actual schools of urbanisms.

whoever has a special place for this subject and ready to share his basics of understanding Urbanism

Rather broad question which needs focus. After all, you can look up the definition yourself in the opening paragraph of any textbook on the subject.

I've read many of those textbooks, with the result that I don't know where to take your inquiry. What would it matter what my personal opinion of it is?

Or, if we run through all the definitions, so what? What we have then is an encyclopedia page where all the various aspects of the term are arrayed.

I'd rather hear that you perceive one or more definitions which clash when placed side-by-side; and that they need reconciling.

That, I could assist you with...