equipment vs stepping-stone

equipment

noun
  • The act of equipping, or the state of being equipped, as for a voyage or expedition. 

  • Any items used in equipping something or someone, for example things needed for an expedition or voyage. 

  • The male genitalia. 

stepping-stone

How often have the words equipment and stepping-stone occurred in a corpus of books? (source: Google Ngram Viewer )