calf vs crus

calf

noun
  • The back of the leg below the knee. 

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

  • A cabless railroad engine. 

  • A young cow or bull. 

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

  • 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. 

crus

noun
  • A leglike part; shank 

  • The shin (tibia and fibula) 

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