earl vs lord

earl

noun
  • A British or Irish nobleman next in rank above a viscount and below a marquess; equivalent to a European count. A female using the style is termed a countess. 

  • Any of various nymphalid butterflies of the genus Tanaecia. Other butterflies in this genus are called counts and viscounts. 

lord

noun
  • One possessing similar mastery over others; (historical) any feudal superior generally; any nobleman or aristocrat; any chief, prince, or sovereign ruler; in Scotland, a male member of the lowest rank of nobility (the equivalent rank in England is baron) 

  • A peer of the realm, particularly a temporal one 

  • One possessing similar mastery in figurative senses (esp. as lord of ~) 

  • A magnate of a trade or profession. 

  • The heavenly body considered to possess a dominant influence over an event, time, etc. 

  • A feudal tenant holding his manor directly of the king 

verb
  • Domineer or act like a lord. 

  • To invest with the dignity, power, and privileges of a lord; to grant the title of lord. 

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