convert vs vary

convert

verb
  • To change (something) from one use, function, or purpose to another. 

  • To express (a quantity) in alternative units. 

  • To score extra points after (a try) by completing a conversion. 

  • To appropriate wrongfully or unlawfully; to commit the common law tort of conversion. 

  • To induce (someone) to adopt a particular religion, faith, ideology or belief (see also sense 11). 

  • To score a spare. 

  • To perform the action that an online advertisement is intended to induce; to reach the point of conversion. 

  • To undergo a conversion of religion, faith or belief (see also sense 3). 

  • To transform a material or positional advantage into a win. 

  • To become converted. 

  • To score (especially a penalty kick). 

  • To change (one proposition) into another, so that what was the subject of the first becomes the predicate of the second. 

  • To express (a unit of measurement) in terms of another; to furnish a mathematical formula by which a quantity, expressed in the former unit, may be given in the latter. 

  • To increase one's individual score, especially from 50 runs (a fifty) to 100 runs (a century), or from a century to a double or triple century. 

  • To transform or change (something) into another form, substance, state, or product. 

  • To exchange for something of equal value. 

noun
  • The equivalent of a conversion in rugby 

  • A person who has converted to a religion. 

  • A person who is now in favour of something that he or she previously opposed or disliked. 

vary

verb
  • To embellish; to change fancifully; to present under new aspects, as of form, key, measure, etc. See variation. 

  • To make of different kinds; to make different from one another; to diversity; to variegate. 

  • To be or act different from the usual. 

  • Not to remain constant: to change with time or a similar parameter. 

  • To institute a change in, from a current state; to modify. 

  • To change with time or a similar parameter. 

  • To display differences. 

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