The Cambridge dictionary gives the following definition of the adjective assistant:
"used as part of someone's job title to show that their job is below the level of a more senior person, and that they help that person to do their job"
Now I'm wondering if this can be used as a synonym for the noun assistant, or if it can only be used for people who are next in line for their superordinate's job. That is, which is the correct use of the following phrases – only the a alternatives or the b alternatives as well as the a alternatives?
- assistant professor
a) '(person who assists a professor), and who will become a professor next time they get a promotion'
b) 'a professor's assistant'
- assistant director
a) '(person who assists a director), and who will become a director next time they get a promotion'
b) 'a director's assistant'
(If my question is bad/not allowed, I'd be very grateful if anyone down-voting it could please tell me in a comment what's wrong with it, because I seem to have some problems understanding what questions are allowed and not...)