manioc vs manioca

manioc

noun
  • Cassava root, eaten as a food. 

  • A food starch prepared from the root. 

  • The tropical plant Manihot esculenta, from which cassava and tapioca are prepared. 

manioca

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