bicoloured vs heterochromatic

bicoloured

adj
  • Of two colours. 

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 bicoloured and heterochromatic occurred in a corpus of books? (source: Google Ngram Viewer )