Merriam-Webster obviously says that the word is an abbreviation for doctor, and I also acknowledge the fact that it's less formal than doctor. My question is: when talking to your doctor, would it be considered rude to call him or her a doc?
I'm examining and touching on your private parts and information, I'm ok with you calling me "Doc". I'm a retired military physician (MD). Concerning military medics (enlisteds) in the field, they are pretty well trained, because they want to be and they have to be. We work hard to give them all the medical training possible. If you get hit or sick out there, the guy treating you is doctoring you. He IS your doctor. England, Australia, Japan, etc, have 6 year medical schools to which high school graduates matriculate without doing a 4 year undergrad program . Also their degrees are bachelor degrees, not "doctors of medicine', but still they are just as good at doctoring as we are over here. "Doc" is neutral, and actually I prefer "Doc" , both in the office and out. No need to call me "Doctor of Medicine" or even "Doctor" . "Doc" differentiates me from others in the room, and refers to what I am here for. To me, the rest of the word or title is superfluous in conversation.
It depends on the relationship. You could call a president "Prez", or a professor "Prof" – either of those would be acceptable English, but whether or not you'd be violating social etiquette is another matter. Some people in authority have no problem with a more informal title, while others might be uncomfortable with it.
Calling your health care provider Doc is like taking a new medication or starting a new exercise regimen: you should consult your doctor first.
As a physician myself, I can say I don't find it particularly offensive.
Plenty of patients refer to me as Doc.
That said, it smacks of country bumpkin. My impression of people who use the term is that they are less sophisticated.
There is also a recent phenomenon of patients calling me by my first name despite never having met before. This, I find a bit disrespectful. I introduce myself as Doctor M., and if a patient asks if they may call me by first name, I have never once said no. But, I rather dislike when people do so without asking. I'd much rather they called me Doc.