habergeon vs third class

habergeon

noun
  • A hauberk, any coat of (chain or scale) mail. 

  • A sleeveless or short-sleeved coat of mail armour (a shorter hauberk). 

  • The quilted undergarment worn under a hauberk. 

third class

noun
  • A reduced-rate mail service for printed matter. 

  • The cheapest accommodation on a train or ship. 

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