cush-cush vs nyami

cush-cush

noun
  • Synonym of couche-couche 

  • A tropical American yam with small yellow-skinned edible tubers: Dioscorea trifida 

nyami

noun
  • Synonym of name (yam) 

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