Residency or postgraduate training is a stage of graduate medical education. It refers to a qualified physician (one who holds the degree of MD, DO, MBBS, MBChB), veterinarian (DVM or VMD), dentist (DDS or DMD), podiatrist (DPM) or pharmacist (PharmD) who practices medicine, veterinary medicine, dentistry, podiatry, or clinical pharmacy, respectively, usually in a hospital or clinic, under the direct or indirect supervision of a senior medical clinician registered in that specialty such as an attending physician or consultant. In many jurisdictions, successful completion of such training is a requirement in order to obtain an unrestricted license to practice medicine, and in particular a license to practice a chosen specialty. In the meantime they practice "on" the license of their supervising physician. An individual engaged in such training may be referred to as a resident, registrar or trainee depending on the jurisdiction. Residency training may be followed by fellowship or sub-specialty training.
Whereas medical school teaches physicians a broad range of medical knowledge, basic clinical skills, and supervised experience practicing medicine in a variety of fields, medical residency gives in-depth training within a specific branch of medicine.
A resident physician is more commonly referred to as a resident, senior house officer (in Commonwealth countries), or alternatively, a senior resident medical officer or house officer. Residents have graduated from an accredited medical school and hold a medical degree (MD, DO, MBBS, MBChB). Residents are, collectively, the house staff of a hospital. This term comes from the fact that resident physicians traditionally spend the majority of their training "in house" (i.e., the hospital).
Duration of residencies can range from three years to seven years, depending upon the program and specialty. A year in residency begins between late June and early July depending on the individual program and ends one calendar year later.