A person who is interned, forcibly or voluntarily.

A student or recent graduate who works in order to gain experience in their chosen field.

A medical student or recent graduate working in a hospital as a final part of medical training.

(transitive) To confine or imprison someone, typically without trial, especially during wartime for foreign military personnel who enter a neutral state's territory.

(transitive, programming) To internalize.

(intransitive) To work as an intern. Usually with little or no pay or other legal prerogatives of employment, for the purpose of furthering a program of education.