fourfold vs quadruple

fourfold

verb
  • to increase to four times as much; to multiply by four 

noun
  • An algebraic variety of degree 4. 

adv
  • by a factor of four 

adj
  • Comprised of four individual members. 

  • Four times as great; quadruple. 

quadruple

verb
  • To multiply by four. 

  • To increase by a factor of four. 

  • To provide four parallel running lines on a given stretch of railway. 

adj
  • Being four times as long, as big or as many of something. 

noun
  • A figure-skating jump with four revolutions in the air. 

  • Something that is four times the usual number, amount, size, etc. 

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