d.o stands for what
These initials refer to the doctor's credentials â they indicate the type of medical school the doctor attended and the licensing exam they took to become a doctor. 1  MD stands for Doctor of Medicine, and is the most common type of degree earned by doctors who practice medicine in the United States. DO stands for Doctor of Osteopathic Medicine, and refers to a doctor who practices medicine whose medical school training included a focus on the muscular and skeletal systems to treat problems throughout the body. Both MD's and DO's attend medical school and take exams to become licensed, practicing physicians.