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 English
Examples from the Corpus
groomsman• We need one groomsman for each bridesmaid.• For the first time Dinah met his publisher, Mr Lamprey, who was the groomsman. 