Groomsman
A male friend or relative who stands beside the groom at the wedding.
Also: groomsmen, usher
A groomsman is a man who stands with the groom at the ceremony, wearing matching clothes, and often helps guests to their seats, in which case he may be called an usher. The number is for the couple to choose. The chief groomsman is the best man. Some couples mix genders, and may call them groomspeople or the wedding party. They are often asked to help with the stag party, with transport and with dancing.