lanolin vs yolk

lanolin

noun
  • A greasy yellow substance chemically akin to wax that is secreted from wooly animals, with a variety of uses from rust prevention, lubrication and waterproofing to cosmetics and skin ointments. 

verb
  • To treat with lanolin. 

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 lanolin and yolk occurred in a corpus of books? (source: Google Ngram Viewer )