apparatus vs stepping-stone

apparatus

noun
  • An assortment of tools and instruments. 

  • The entirety of means whereby a specific production is made existent or task accomplished. 

  • A complex machine or instrument. 

  • A vehicle used for emergency response. 

  • A bureaucratic organization, especially one influenced by political patronage. 

  • Any of the equipment on which the gymnasts perform their movements. 

  • A complex, highly modified weapon (typically not a firearm); a weaponized “Rube Goldberg machine.” 

stepping-stone

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