old lady vs viscountess

old lady

noun
  • A queen. 

  • The Bank of England, sometimes referred to as the “Old Lady of Threadneedle Street” or simply “The Old Lady”. 

  • One's mother. 

  • An elderly woman. 

  • One's girlfriend, wife or significant other. 

viscountess

noun
  • The wife of a viscount. 

  • A woman holding the rank of viscount in her own right. 

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