bun 1 
(bŭn)
(bŭn)n.
1.
a. An unsweetened round or oblong roll, used especially to hold a hamburger patty or a hot dog.
b. A small sweetened roll, often spiced or containing dried fruit.
2. A tight roll of hair worn at the back of the head.
[Middle English bunne, probably from Old French bugne, boil, of Celtic origin.]