goad vs yolk

goad

noun
  • A long, pointed stick used to prod animals. 

  • That which goads or incites; a stimulus. 

verb
  • To encourage or stimulate. 

  • To incite or provoke. 

  • To prod with a goad. 

yolk

noun
  • The grease in a sheep's fleece; lanolin. 

  • The yellow, spherical part of an egg that is surrounded by the white albumen, and serves as nutriment for the growing young. 

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