monochrome vs unicolor

monochrome

adj
  • Having only one colour. 

  • Representing colours with shades of gray. 

noun
  • A ceramic glaze of a single colour; an object so glazed. 

  • A black and white image, especially such a photograph. 

unicolor

adj
  • Of one color; monochromatic. 

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