medical intern vs Dr.

medical intern and Dr. both are nouns.

Word	Noun	Adjective	Verb	Adverb
medical intern	Yes	No	No	No
Dr.	Yes	No	No	No

As nouns, Dr. is a hypernym of medical intern; that is, Dr. is a word with a broader meaning than medical intern:

medical intern: an advanced student or graduate in medicine gaining supervised practical experience
Dr.: a licensed medical practitioner

Other hypernyms of medical intern include doc, doctor, MD, medico, physician.

medical intern (noun)	Dr. (noun)
an advanced student or graduate in medicine gaining supervised practical experience	a licensed medical practitioner
	a person who holds Ph.D. degree (or the equivalent) from an academic institution