amelioration vs recension

amelioration

noun
  • An ameliorative change of a concept or a repertoire of concepts. 

  • The act of making better. 

  • An improvement. 

  • The process by which a term gains a more positive connotation over time. 

recension

noun
  • A text established by critical revision. 

  • A family of manuscripts which share similar traits; the variety of a language which is used in such manuscripts. 

  • A critical revision of a text. 

  • A census, an enumeration, a review, a survey. 

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