carbuncle

Short definition from Wiktionary

Noun

1. 1
   A deep-red or fiery colored garnet or other dark red precious stone, especially when cut cabochon.
2. 2
   A charge or bearing supposed to represent the precious stone, with eight sceptres or staves radiating from a common centre; an escarbuncle.
3. 3
   An abscess larger than a boil, usually with one or more openings draining pus onto the skin. It is usually caused by staphylococcal infection.
4. 4
   An unpopular or ugly building; an eyesore.