A sequin is a very small disc of plastic used in crafts and dress making for embellishment. They are most commonly sewn on in mass for evening dresses and dance costumes.

Sequins are commonly manufactured by a stamping process that leaves multiple facets around the disc face, much like the facets of a cut diamond. Sequins are also found in metallic, reflective colors to increase their glitz and glitter. Sequins have a small hole in the middle of them to allow a thread to pass through so it may be sewn onto fabric. 

Sequins fabric is often used for fancy clothes in mass quantities as decoration, the overall effect is a glamorous shimmer or shine for this reason they are used by fashion designers regularly on evening dresses and or by costume designers on dance costumes.

Sequins can be purchased from sewing stores or a specialist button supplier.