Hospitals are institutions designed to care for the sick, injured, and well. A hospital provides complete health care including curative and preventive services. It serves as a center for training health workers and conducting biomedical research. Hospitals can be classified based on length of stay, clinical focus, ownership, objectives, size, management, and medical system. They perform key functions like patient care, diagnosis and treatment, outpatient services, medical education, research, and disease prevention and health promotion.