extensional vs kosher

extensional

adj
  • Having great extent. 

  • Of or pertaining to extension. 

kosher

adj
  • In accordance with standards or usual practice. 

  • Fit for use or consumption, in accordance with Jewish law (especially relating to food). 

adv
  • In a kosher manner; in accordance with kashrut. 

verb
  • To kasher; to prepare (for example, meat) in conformity with the requirements of the Jewish law. 

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