eldest vs primogeniture

eldest

noun
  • The eldest child in a family, or individual in a group. 

adj
  • (of a hand) Having higher, or superior cards. 

  • (of a player) Receiving cards from the dealer first, before any other players. 

primogeniture

noun
  • The state of being the firstborn of the children of the same parents. 

  • An instance of such a right of inheritance, established by custom or law. 

  • The principle that the eldest child, traditionally the eldest male, has an exclusive right of inheritance. 

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