hoof vs shoe tree

hoof

noun
  • The human foot. 

  • The tip of a toe of an ungulate such as a horse, ox or deer, strengthened by a thick keratin covering. 

verb
  • To trample with hooves. 

  • To dance, especially as a professional. 

  • To kick, especially to kick a football a long way downfield with little accuracy. 

  • To walk. 

shoe tree

noun
  • A device approximating the shape of a foot that is placed inside a shoe when it is being stored to preserve its shape and extend the life of the shoe. 

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