car·bun·cle
kar buhng kəl
noun
1. a dark gemstone, especially a ruby sapphire.
quotation: A golden chain hung about his neck, and at his collar was a great carbuncle set in red gold. (Howard Pyle, The Legend of Robin Hood)
2. a painful localized abscess of the tissue underneath the skin.
quotation: He was a man well stricken in years, but still strong to do evil: he was one who looked cruelly out of a hot, passionate, bloodshot eye; who had a huge red nose with a carbuncle, thick lips, and a great double, flabby chin, which swelled out into solid substance, like a turkey-cock’s comb, when sudden anger inspired him. (A. Trollope, The Warden)