nitty : Idioms & Phrases

• noun the choicest or most essential or most vital part of some idea or experience
  kernel; substance; center; centre; essence; sum; meat; heart; pith; nub; heart and soul; core; inwardness; marrow; gist.
  
  • the gist of the prosecutor's argument
  • the heart and soul of the Republican Party
  • the nub of the story

WordNet