The term 'graduation costume' typically refers to the formal attire worn by students during their graduation ceremony. The most common item of clothing for this occasion is a GOWN, which is a long, loose-fitting garment with long sleeves and a high neckline. It is usually made of a lightweight fabric such as silk or satin and is often decorated with embroidery or other embellishments. Gowns are traditionally worn with a mortarboard hat, which is a flat square cap with a tassel attached to the top.