ankle vs instep

ankle

noun
  • The skeletal joint which connects the foot with the leg; the uppermost portion of the foot and lowermost portion of the leg, which contain this skeletal joint. 

verb
  • To walk. 

  • To cyclically angle the foot at the ankle while pedaling, to maximize the amount of work applied to the pedal during each revolution. 

instep

noun
  • The arched part of the top of the foot between the toes and the ankle. 

  • In horses, the hind leg from the ham to the pastern joint. 

  • A section of any footwear covering that part of the foot. 

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