ergo vs hereof

ergo

adv
  • Consequently, therefore, or thus. 

noun
  • An ergonomic factor or characteristic. 

conj
  • therefore (especially in syllogisms) 

hereof

adv
  • From or as a result of this. 

  • Of this; concerning this. 

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