Pronunciation: (bun),[key] —n. 1. any of a wide variety of variously shaped bread rolls, usually leavened and slightly sweetened or plain, sometimes containing spices, dried currants, etc.
2. hair gathered into a round coil or knot at the nape of the neck or on top of the head in certain coiffures.
3. buns,Slang.the buttocks.
Pronunciation: (bun),[key] —n. have a bun on,Slang.to be intoxicated: Everyone at the party seemed to have a bun on.
blood urea nitrogen: the concentration of nitrogen in the blood in the form of urea, indicating kidney function.