airmail vs dak

airmail

noun
  • The system of conveying mail using aircraft. 

  • The items of mail so carried. 

verb
  • To send mail by air. 

  • To (unintentionally) throw the ball well over a fielder's head where that fielder is unable to make a play on the ball. 

dak

noun
  • A post system by means of transport relays of horses stationed at intervals along a route or network, carrying mail and passengers. 

  • A dak bungalow. 

verb
  • To suddenly pull down someone's pants as a prank; to pants. 

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