noun
outer sash
A decorative sash tied over the obi of a kimono, often used in traditional dress.
着物の上に上帯を締める。
I tie an outer sash over the kimono.
帯 is the main sash worn around the waist; 上帯 is an additional decorative sash worn over it.
Compound of 上 (うわ, 'upper') and 帯 (おび, 'sash').