black cumin vs earthnut

black cumin

noun
  • A spice plant with aromatic seeds (Nigella sativa). 

  • A cultivated variety of cumin (Cuminum cyminum). 

  • A spice plant related to cumin with dark seeds and an edible root (Bunium bulbocastanum). 

earthnut

noun
  • The dwarf ginseng: Panax trifolius 

  • The underground tuber belonging to the genus Tuber; the truffle. 

  • Synonym of peanut (Arachis hypogaea) 

  • A tuber belonging to the species Conopodium majus (syns. Bunium flexuosum, Conopodium denudatum), Bunium bulbocastanum (syn. Carum bulbocastanum), or Apios americana (syn. Apios tuberosa) 

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