1. 
[syn: kernel, substance, core, center, centre, essence, gist, heart, heart and soul, inwardness, marrow, meat, nub, pith, sum, nitty-gritty]
WordNet (r) 3.0 (2006):
nitty-gritty
    n 1: 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" [syn: kernel, substance, core,
         center, centre, essence, gist, heart, heart and
         soul, inwardness, marrow, meat, nub, pith,
         sum, nitty-gritty]