best man vs flower girl

best man

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

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

flower girl

noun
  • A participant in a wedding procession, whose responsibility is usually to spread flower petals on the floor before the bride, or to carry a bouquet of flowers. 

  • A female flower child. 

  • A girl who sells flowers. 

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