Cortisone is a hormone, and also a medicine built on that hormone. Doctors have used it, especially in the past, to calm swelling and to treat things like arthritis — joints that are sore and inflamed. In everyday talk in Taiwan, people often fold it into the larger group they just call 類固醇. Though actually, in careful medical talk cortisone is one specific compound; cortisol is the main 'stress hormone' the adrenal glands send out, and a cream or a pill may contain a related medicine, not necessarily cortisone itself. The name is a shortened form of corticosterone, which points to the cortex of the adrenal gland — the outer layer that makes hormones of this type. It is a hospital-and-pharmacy word, not a casual one.