linchpin vs sinew

linchpin

noun
  • A central cohesive source of stability and security; a person or thing that is critical to a system or organisation. 

  • A pin inserted through holes at the end of an axle or shaft, so as to secure a wheel or shaft-mounted device. 

verb
  • To adopt as, or serve as, a central cohesive source of stability and security. 

sinew

noun
  • That which gives strength or in which strength consists; a supporting factor or member; mainstay. 

  • A cord or tendon of the body. 

  • A cord or string, particularly (music) as of a musical instrument. 

  • Muscular power, muscle; nerve, nervous energy; vigor, vigorous strength. 

verb
  • To knit together or make strong with, or as if with, sinews. 

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