special delivery vs third class

special delivery

noun
  • A kind of postal service in which, for an extra fee, letters and packages are delivered in a highly expedited manner by a special courier. 

  • A particular posted letter or package which is delivered in this manner; a particular act of conveying such letters or packages to one or more recipients. 

  • Something—whether desirable or undesirable—which is intentionally given to a specific individual or which an individual receives rapidly and unexpectedly; the personalized, direct quality of the transmission of such an item. 

third class

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

  • The cheapest accommodation on a train or ship. 

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