[pbhjpbhj]

You're correct that parents provide a monopoly on working an invention and do not legally inhibit publicising an invention (as you note, that is one of their aims).

>The word means “make obvious”.//

"Patent" means "open", it comes from a Latin phrase meaning "open letter". Patents were originally letters from the monarch to their subjects on all sorts of issues. When monopolies were granted on working inventions people were notified by the issue of a litterae patentes (some people still style it "letters patent" in British English). This mode of acquiring rights stuck and the name became synonymous.

Patents do have to disclose in detail how an invention can be worked ('sufficiency' in UK law).