completion vs onset

completion

noun
  • The act or state of being or making something complete; conclusion, accomplishment. 

  • The space resulting from such an act. 

  • The conclusion of an act of conveyancing concerning the sale of a property. 

  • The act of making a metric space complete by adding points. 

  • A forward pass that is successfully caught by the intended receiver. 

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. 

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