duet vs marriage

duet

noun
  • A pair or couple, especially one that is harmonious or elegant. 

  • A musical composition in two parts, each performed by a single voice (singer, instrument or univoce ensemble). 

  • A song composed for and/or performed by a duo. 

verb
  • To perform (sing, play, etc.) as a duet. 

  • (of two people) To say at the same time, to chorus. 

  • To perform a duet. 

  • To communicate (warnings, mating calls, etc.) through song. 

marriage

noun
  • A wedding; a ceremony in which people wed. 

  • The union of two people of opposite sex, to the exclusion of all others. 

  • A close union. 

  • In solitaire or patience games, the placing a card of the same suit on the next one above or below it in value. 

  • A union of two or more people that creates a family tie and carries legal, social, and/or religious rights and responsibilities. 

  • A king and a queen, when held as a hand in some versions of poker or melded in pinochle. 

  • The state of being married. 

  • A homosexual relationship between male prisoners. 

  • The union of only two people, to the exclusion of all others. 

  • A joining of two parts. 

  • My grandparents' marriage lasted for forty years. 

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