rusk vs tortilla

rusk

noun
  • a rectangular, hard, dry biscuit 

  • a twice-baked bread, slices of bread baked until they are hard and crisp (also called a zwieback) 

  • a cereal binder used in meat product manufacture 

  • a weaning food for children 

tortilla

noun
  • A flat round bread made out of cornmeal or flour. 

  • Spanish omelette; an omelette containing potatoes and onions. 

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