melanoid vs pitch-dark

melanoid

noun

  • Synonym of melanoidin 

adj

  • Relating to, or afflicted with, melanosis. 

  • Relating to, or resembling, melanin. 

pitch-dark

adj

  • Absolutely dark or black; as dark as pitch. 

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