elderdom vs imperium

elderdom

noun
  • Authority; dominion. 

  • Preeminence; superiority. 

  • The role or influence of an elder or elders. 

  • The authority, rule, or office of an elder. 

  • The state of being an elder, or of being older; elderhood. 

imperium

noun
  • Supreme power; dominion. 

  • The right to command the force of the state; sovereignty. 

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