ingroup vs inner circle

ingroup

noun
  • The social group that one belongs to. 

  • In cladistics, the monophyletic group that includes all taxa of interest to the current study. 

verb
  • To form an ingroup. 

inner circle

noun
  • The group comprising one's closest friends or associates. 

  • Used other than figuratively or idiomatically: see inner, circle. 

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