melanoid vs piceous

melanoid

noun

  • Synonym of melanoidin 

adj

  • Relating to, or afflicted with, melanosis. 

  • Relating to, or resembling, melanin. 

piceous

adj

  • Resembling pitch in colour; a very dark brown. 

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