noblewoman vs peeress

noblewoman

noun
  • A woman having a noble rank, especially one belonging to the peerage; a Lady. 

peeress

noun
  • A woman holding a noble title in her own right. 

  • A noblewoman married to a peer. 

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