bicolour vs heterochromatic

bicolour

adj
  • Having two colours 

noun
  • A flower, cat etc., that has two colours. 

  • A flag with such colours, consisting of two stripes that are either vertical or horizontal. 

heterochromatic

adj
  • Having more than one colour; relating to heterochromia. 

  • Of light, having more than one wavelength. 

  • Of or relating to heterochromatin. 

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