These two seem to get about the same googlpressions, which got me wondering whether 'doctor's visit' perhaps arose at a time when the doctor always can *to the patient. But although most generally go to the doctor themselves now, some still say, "I have a doctor's visit", even though it is really a 'patient's visit' or 'a visit to the doctor' they mean. Leaving the apostrophe out doesn't change this either, but I have the inclination to do so for some reason. What say the MDs? don't tell me - 'It's a consultation':-)