doctors appointments or doctor's appointments or doctors' appointments [duplicate]

I've looked this up online, but I can't find any explanations from reasonably credible sources, so I'm posting my question here! (Was that a comma splice?)

Should I refer to the appointment that I made with my doctor as a "doctor's appointment" or "doctors appointment"? What if I'm referring to more than one appointment with two different doctors?

As the doctor also has an appointment with you, doctor's appointment is appropriate in its own right. It is also by far the most common as a set phrase:

Any other plural usage would be entirely subjective.

Graph source: Google Books Ngram

You can use either doctor appointment or doctor's appointment. Merriam-Webster indirectly supports the latter with its second example under its listing for appointment.

I agree with tchrist that the word doctor in doctor appointment is a noun (attributive noun I believe), although the definition of an attributive noun is a noun used as an adjective, so maybe it's just semantics at some point.

To the point above about the appointment being reciprocal, I can sort of get on board with that. I suppose the doctor does have an appointment with the patient as well, but I think the emphasis is a bit off in that perspective because I think the ownership pertains more directly to the patient (just my take).

In any case, you should be okay with either usage above.