A type of single hair bun/double bun where the hair is rolled using a hairdressing item called a hair doughnut, rather than coiling hair around repeatedly as seen in the traditional odango-styled hair bun. The resulting hair bun indeed resembles a circular doughnut.
If you're having trouble discerning the difference between a doughnut-shaped hair bun and an odango-shaped hair bun in an image, it is best not to use this tag.
