Carbuncle Car"bun*cle, n. [L. carbunculus a little coal, a bright kind of precious stone, a kind of tumor, dim. of carbo coal: cf. F. carboncle. See Carbon.] 1. (Min.) A beautiful gem of a deep red color (with a mixture of scarlet) called by the Greeks anthrax; found in the East Indies. When held up to the sun, it loses its deep tinge, and becomes of the color of burning coal. The name belongs for the most part to ruby sapphire, though it has been also given to red spinel and garnet. 2. (Med.) A very painful acute local inflammation of the subcutaneous tissue, esp. of the trunk or back of the neck, characterized by brawny hardness of the affected parts, sloughing of the skin and deeper tissues, and marked constitutional depression. It differs from a boil in size, tendency to spread, and the absence of a central core, and is frequently fatal. It is also called anthrax. 3. (Her.) A charge or bearing supposed to represent the precious stone. It has eight scepters or staves radiating from a common center. Called also escarbuncle.