aquarelle vs watercolour

aquarelle

noun
  • A watercolour (painting) 

  • A printed picture coloured by the application of watercolour through stencils, using a different stencil for each colour. 

watercolour

noun
  • A painting made by using such pigment. 

  • This kind of painting as a genre. 

  • A water-soluble pigment. 

adj
  • Pertaining to the methods or products of watercolor. 

verb
  • To paint using watercolour 

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