email vs special delivery

email

noun
  • A message sent through an email system. 

  • An email address. 

  • A system for transferring messages from one computer to another, usually through a network. 

  • A quantity of messages sent through an email system. 

verb
  • To send (something) through email. 

  • To send, or compose and send, an email or emails. 

  • To send an email or emails to. 

special delivery

noun
  • 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. 

  • 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. 

  • 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. 

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