groomsman
From Longman Dictionary of Contemporary Englishgroomsmangrooms‧man /ˈɡruːmzmən, ˈɡrʊms-/ noun (plural groomsmen /-mən/) [countable] American EnglishMARRY a friend of a bridegroom who has special duties at a wedding SYN best man British EnglishExamples from the Corpusgroomsman• We need one groomsman for each bridesmaid.• For the first time Dinah met his publisher, Mr Lamprey, who was the groomsman.