best man vs bridesman

best man

noun
  • The primary attendant to the groom in a wedding ceremony. 

  • Used other than figuratively or idiomatically: see best, man. 

bridesman

noun
  • A male friend or companion of the bridegroom, having various ceremonial duties at a wedding. 

  • A male bridesmaid; a man who attends a bride during her wedding ceremony, as part of the wedding party. 

How often have the words best man and bridesman occurred in a corpus of books? (source: Google Ngram Viewer )