chi vs kappa

chi

noun
  • The twenty-second letter of the Classical and Modern Greek alphabets. 

  • The Chinese foot, a traditional Chinese unit of length based on the human forearm. 

  • A life force in traditional Chinese philosophy, culture, medicine, etc, related (but not limited) to breath and circulation. 

  • The Chinese unit of length standardized in 1984 as ¹/₃ of a meter. 

  • The Taiwanese unit of length standardized as ¹⁰/₃₃ of a meter, identical to the Japanese shaku. 

  • The chek or Hong Kong foot, a unit of length standardized as 0.371475 meters. 

kappa

noun
  • The tenth letter of the Greek alphabet. 

  • A measurement of the sensitivity of the value of an option to changes in the implied volatility of the price of the underlying asset. 

  • A tortoise-like demon or imp. 

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