A bun is a type of hairstyle wherein the hair is pulled back from the face, twisted or plaited, and wrapped in a circular coil around itself, typically on top or back of the head or just above the neck. A bun can be secured with a barrette, bobby pins, one or more hair sticks, a hairnet, or a pen or pencil. Hair may also be wrapped around a piece called a "rat". Alternatively, hair bun inserts, or sometimes rolled up socks, may also be used to create donut-shaped buns. Buns may be tightly gathered, or loose and more informal.
Bun (hairstyle) Wikipedia
Double or pigtail buns are often called odango (お団子, odango) , which is also a type of Japanese dumpling (usually called dango; the o- is honorific).
The term was popularized by the anime and manga series Sailor Moon, whose eponymous heroine, her mother during the Ancient Silver Millennium, Queen Serenity, and her future daughter from the 30th Century Silver Millennium, Chibiusa (although Chibiusa's are more conical than spherical), all wear their hair in this style. They also wear two pigtails of hair that hang down from the two spherical buns, but this is not universal to the term's usage within Japan, itself. The term odango in Japanese can refer to any variety of bun hairstyle.
In China, the hairstyle is called niújiǎotóu (牛角头). It was a commonly used hairstyle up until the early 20th century, and can still be seen today when traditional attire is used. This hairstyle differs from the odango slightly in that it is gender neutral; Chinese paintings of children have frequently depicted girls as having matching ox horns, while boys have a single bun in the back.
Although man buns were worn in China as early as 200BC as depicted on the terracotta soldiers. They were worn until the end of the Ming Dynasty in 1644AD, after which the Qing Dynasty government enforced Han Chinese to adopt the queue hairstyle (queue order).
The term "man bun" is a term used to describe long-haired men who do not wish to sport the traditional trend of short back and sides wearing their hair in a topknot. It originated in 16th century Japan as the traditional hairstyle for samurai warriors and sumo wrestlers
Historical and iconic examples of men with long hair using this style as practicality include:Shiva
6th-7th century BCE — Buddha
3rd century BCE—Terracotta Warriors of China
George Harrison, in the 1970s
Clay Matthews III