A bun is a sweet or plain small bread or a round roll. It can be designed to be cut in half and filled with ingredients, to be made into a sandwich or can be consumed "as is."

Types of Bun

• Hot cross bun
• Spiced bun
• Man tou - Chinese steamed bun
• Hambuger bun
• Hotdog bun

On a sidenote, it's also a reference to the behind, albeit in the form of buns. It also may refer to a hairstyle in which the hair is pulled back and tied up.