A ribbon is a thin band of flexible material, typically cloth but also plastic or sometimes metal, used primarily for binding and tying. Often seen used in elaborate clothing and hair, and generally longer than it is wide.
A ribbon may be tied into any sort of knot, often a bow, but should not be tagged as both.
Example Danbooru post #844003: On top of her hair is some ribbon, but the ribbon tying the hair tails together is a bow.
