| 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. |

| blood urea nitrogen: the concentration of nitrogen in the blood in the form of urea, indicating kidney function. |
BUN abbr.
blood urea nitrogen
| BUN blood urea nitrogen |