What is an internship and in what industries do they have internships? In Science?

Question

What exactly is an "internship" ? What types of industries do they usually have them in? Science? Engineering? Anything else?

Answer 1

Intern means:

a) Junior doctor in hospital: a doctor who has recently graduated from medical school and is receiving practical supervised training in a hospital.

b) Trainee: an assistant or trainee working to gain practical experience in an occupation.

It is just added by a suffix "ship" which maybe means "connection".

And medicinal engineering industries have them.