A groomsman (North America) or usher (British Isles) is one of the male attendants to the groom in a wedding ceremony. Usually, the groom selects close friends and relatives to serve as groomsmen, and it is considered an honor to be selected. From his groomsmen, the groom usually chooses one to serve as best man.
For a wedding with many guests, the groom may also ask other male friends and relatives to act as ushers without otherwise participating in the wedding ceremony; their sole task is ushering guests to their seats before the ceremony. Ushers may also be hired for very large weddings.
In a military officer's wedding, the roles of groomsmen are replaced by swordsmen of the sword honor guard. They are usually picked as close personal friends of the groom who have served with him. Their role includes forming the traditional saber arch for the married couple and guests to walk through.