flagship vs kingpin

flagship

noun
  • The most important one out of a related group. 

  • The ship occupied by the fleet's commander (usually an admiral); it denotes this by flying his flag. 

  • The ship regarded as most important out of a group, e.g. a nation's navy or company's fleet. 

verb
  • To act as a flagship for. 

kingpin

noun
  • The most important person in an undertaking or organization. 

  • The axis around which steered wheels pivot; a bolt that holds the axis in place—a kingbolt. 

  • The bolt holding together the truck of a roller skate or skateboard. 

  • The pivot or connector between a tractor and trailer in the fifth-wheel coupling of semi-trailer truck. 

  • The pin at the centre of the triangle of bowling pins (originally the tallest pin in kayles). Sometimes also the headpin at the apex. 

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