student, economics, medical, occupation

Is it better to say “student of economics” or “economics student”.
Does “medical student” mean “student of medicine”?
Is word “medicine” sometimes equal in meaning to “medical science”?

Can we consider “student” as occupation?
Person A: What is his occupation?
Person B: He is a student?

Or the person B should have said, for example, He will be a dentist.

Thanks

Yes to all those questions.
Occupation: student - is appropriate for someone who is studying full time, whether it is in school, college, university or other place of learning where an authorised learning course is established

A guy redesigns interiors of restaurants? What could be his occupation? Thanks

Interior designer

Can we say “lecturer” can be an occupation or it is a rank within the title of a professor, and the occupation is “professor”?

A: What are their occupations?
B: Jim is a lecturer. Johny is an associate professor and Joan is a professor.

Should B say,‘All three are professors.’

Thanks

B should not say ’ all three are professors’ unless Jim is a professor.
It is possible to be a professor without being a lecturer and to be a lecturer without being a professor.