equal vs vary

equal

verb
  • To make equivalent to; to cause to match. 

  • To have as its consequence. 

  • To be equal to, to have the same value as; to correspond to. 

noun
  • A person or thing of equal status to others. 

adj
  • Intended for voices of one kind only, either all male or all female; not mixed. 

  • Adequate; sufficiently capable or qualified. 

  • The same in all respects. 

  • Exactly identical, having the same value. 

vary

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

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

  • 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 equal and vary occurred in a corpus of books? (source: Google Ngram Viewer )