double appointment

noun3

1. •
   (UK, Australia) An appointment with a GP (general practitioner) which is allocated twice much time as usual.

   • It would help if patients who know they have a difficult problem could book a double appointment, […] — 1998
2. •
   An appointment time with two people assigned to it; a double booked appointment.

   • It's very important that the system is effective, that everything is well registered so we don't end up double-booking doctors or have patients with double appointments[.] — 2018
3. •
   The appointment of a person to two different positions simultaneously.