gist
The main point, overarching theme, essence—that's gist in a nutshell. The gist of gist, if you will. The gist of a conversation, argument, story, or what-have-you is what we rely on when the actual words and details are only imperfectly recalled, inessential, or too voluminous to recount in their entirety. Gist was borrowed from the Anglo-French legal phrase laccion gist ("the action lies/is based [on]") in the 17th century, and it was originally used in law as a term referring to the foundation or grounds for a legal action without which the action would not be legally sustainable.