etch vs xylograph

etch

verb
  • To cut into a surface with an acid or other corrosive substance in order to make a pattern. Best known as a technique for creating printing plates, but also used for decoration on metal, and, in modern industry, to make circuit boards. 

  • To engrave a surface. 

  • To make a lasting impression. 

  • To sketch; to delineate. 

xylograph

verb
  • To make a print from an engraving in wood. 

noun
  • A print taken from such an engraving. 

  • An engraving in wood or woodcut, especially one used in printing predating the Western tradition (14th c.). 

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