pretzel vs rusk

pretzel

noun
  • A toasted bread or cracker usually in the shape of a loose knot. 

  • Anything that is knotted, twisted, or tangled. 

verb
  • To bend, twist, or contort. 

rusk

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

  • a rectangular, hard, dry biscuit 

  • a cereal binder used in meat product manufacture 

  • a weaning food for children 

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