- You may be looking for The Doctor, the EMH of the USS Voyager.
A doctor is a person who has the highest degree awarded by a university in their discipline. This title may refer to an Doctor of Medicine (MD) or a Doctor of Science. (Star Trek: The Motion Picture; TNG: "Up The Long Ladder")
In Lyran educational parlance, the title of doctor could also refer to a Doctor of Pharmacy (Pharm.D.) as well as the aforementionned uses of the title. (Star Trek: The Stoneship Files: "Educational Armageddon")
Lyrans could also refer to a Doctor of Audiology (AuD). (Star Trek: The Stoneship Files: "Express Delivery")
In the U'lanna educational system, Doctor of Sexology (SexD) degrees were also granted. (Star Trek: The Stoneship Files: "For a New World")
Lyran ergotherapists held a degree called a Doctor of Ergotherapy (ErgD). (Star Trek: False Vacuum: "Asteroid Dusting")