A carbuncle or escarbuncle is a heraldic charge consisting of eight radiating rods or spokes, four of which make a common cross and the other four a saltire.
The ends typically terminate in a fleur-de-lis or some other decorative form.
[1] Frequently the centrepoint is adorned with a jewel; the name may therefore be a reference to a carbuncle gemstone though in heraldry the jewel need not be red.
It has its origins in the iron bands and bosses historically used to strengthen shields.
[2] The name may therefore be derived from the Old French boucle, meaning a shield boss.