groomsman

noun

1. A man who serves as one of a number of attendants to a bridegroom at a wedding, one of whom is the best man.

   “The Scotchman, who assisted as groomsman, was of course the only one present, beyond the chief actors, who knew the true situation of the contracting parties.”

   “1888, Horatio Alger, The Errand Boy, Chapter XIV: Consulting the Oracle, "Philip," said Mr. Wilbur, "when I marry, I want you to stand up with me--to be my groomsman."”

   “There were eight bridesmaids and groomsmen, and I asked McClellan and Franklin to be of the number, but distant service prevented them from coming, and Burnside and Reno, of the Ordnance, took their places.”