MD: Abbreviation for the Latin title Medicinae Doctor, Doctor of Medicine. Sometimes written today as MD (without the period after each letter).
All medical schools in the United States and Canada award an M.D. degree, usually after 4 years undergraduate study at a college or university followed by 4 years of medical school. (Some medical schools award the M.D. after 3 years of college and/or 3 years of medical school).
In the U.K., the MBChB, the Bachelor of Medicine and Bachelor of Surgery degrees, are awarded after 5 years of what is analogous to a combined undergraduate-graduate course of study.