modify vs variate

modify

verb
  • To be or become modified. 

  • To change part of. 

  • To set bounds to; to moderate. 

  • To qualify the meaning of. 

variate

verb
  • To alter; to vary; to make or become different. 

noun
  • The measured magnitude of a variable. 

  • random variable 

  • A variable, often the set of x values plotted on a graph. 

  • A measurable quantity capable of taking on a number of values. 

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