noun
attendant; best man; maid of honor; bridesmaid; groomsman
A person who accompanies and assists someone, especially in formal or ceremonial contexts. In weddings, it refers to the best man, maid of honor, bridesmaid, or groomsman. The role is to support the main person.
結婚式で、彼は友人の付き添い役を務めた。
At the wedding, he served as his friend's best man.
花嫁の付き添い役として、妹が選ばれた。
Her younger sister was chosen as the bride's maid of honor.
Compound of 付き添い (tsukisoi, 'attending, accompanying') + 役 (yaku, 'role, duty').