etch vs monoprint

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. 

monoprint

verb
  • To print using this technique. 

noun
  • A form of printing on paper from a glass sheet to which oil paint has been applied; monotype. 

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