onset vs starting point

onset

noun
  • A setting about; a beginning. 

  • The initial portion of a syllable, preceding the syllable nucleus. 

  • The beginning of a musical note or other sound, in which the amplitude rises from zero to an initial peak. 

  • The initial phase of a disease or condition, in which symptoms first become apparent. 

starting point

noun
  • The place where a journey starts. 

  • The first steps when commencing an activity. 

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