A term often applied to a physician, nurse, or dentist whose field of special training, experience, and, usually, practice is a subdivision of a broader specialty. For example, a cardiologist is a physician who has narrowed his field from the specialty of all of internal medicine to the subspecialty concerned with just the diseases of the heart and circulatory system (cardiology). This development might perhaps more accurately have been termed “superspecialization” rather than “subspecialization.”