The term HOSP. EMERGENCY UNITS can be broken down into two parts: HOSP, which stands for Hospital, and EMERGENCY UNITS, which refers to the personnel who provide EMERGENCY services in a hospital. The three-letter acronym ERS stands for EMERGENCY Room Staff, which is a group of medical professionals who are responsible for providing EMERGENCY care to patients in a hospital. They are typically composed of doctors, nurses, and other medical personnel who specialize in EMERGENCY medicine.