occasion vs sire

occasion

verb
  • To cause; to produce; to induce 

noun
  • Need; requirement, necessity. 

  • The time when something happens. 

  • Something which causes something else; a cause. 

  • A reason or excuse; a motive; a persuasion. 

  • A special event or function. 

  • A particular happening; an instance or time when something occurred. 

  • An occurrence or state of affairs which causes some event or reaction; a motive or reason. 

  • A favorable opportunity; a convenient or timely chance. 

sire

verb
  • to father; to beget. 

noun
  • A male animal that has fathered a particular offspring (especially used of domestic animals and/or in biological research). 

  • A lord, master, or other person in authority, most commonly used vocatively: formerly in speaking to elders and superiors, later only when addressing a sovereign. 

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