calf vs yolk

calf

noun
  • Leather made of the skin of the calf; especially, a fine, light-coloured leather used in bookbinding. 

  • A chunk of ice broken from a larger glacier, ice shelf, or iceberg. 

  • A cabless railroad engine. 

  • The back of the leg below the knee. 

  • A young cow or bull. 

  • A young deer, elephant, seal, whale or giraffe (also used of some other animals). 

  • The muscle in the back of the leg below the knee. 

  • A small island, near a larger island. 

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