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.