gist in WordNet English dictionary

1. the central meaning or theme of a speech or literary work
   effect  essence  burden  core  gist 
   
2. the choicest or most essential or most vital part of some idea or experience
   "the gist of the prosecutor's argument"; "the heart and soul of the Republican Party"; "the nub of the story"
   kernel  substance  core  center  centre  essence  gist  heart  heart and soul  inwardness  marrow  meat  nub  pith  sum  nitty-gritty