What is the meaning of gist?

noun

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