I wasn't thinking about this when i started this thread, but i think that "medicine" as an abbreviation of "internal medicine" is possibly the strangest thing. A conversation with my new housemate-for-the-summer and me, five years ago:
Me: So, what are you doing here?
Her: I'm just starting my internship at the hospital here.
Me: Hey, me too! I'm an intern for Dr. So and So this summer.
Her: No, I mean, this is my first year of my residency. I just got my M.D. last month.
Me: Oh, cool! What field are you doing your residency in?
Her: Medicine.
Me: I understand. But what field?
Her: Medicine.
Me: I get it. I mean, what kind of internship are you doing?
Her: You don't get it. I'm not doing a summer undergrad internship like you are. I'm a doctor, and I'm going into medicine.
Me: Right, I understood that. You're a doctor. I get it. So of course you're doing medicine. But what field?
Her: *walks away*