Residency is "a 3+ year training program in a medical specialty. The first year of training after medical school is called internship, or more commonly it is called first year of residency or PGY-1 (PostGraduate Year-1). The following years are called PGY-2, PGY-3, etc. The training that is done after a residency (in a subspecialty) is usually called a fellowship." [1]