The term BUN OR BEEHIVE can refer to two different hairstyles. The first is an updo, which is a four-letter term for a hairstyle that is pinned or tied up at the back of the head. The second is a HAIRDO, which is a six-letter term for a hairstyle that is styled and arranged in a particular way. Both of these hairstyles involve the hair being pulled back and secured in some way, either with a bun or a beehive shape.