changing vs recension

changing

noun
  • Change; alteration. 

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 changing and recension occurred in a corpus of books? (source: Google Ngram Viewer )