Synonyms for Gist (same or very similar meaning)
WordNet sense 1 (the central meaning or theme of a speech or literary work):
burden, core, effect, essenceWordNet sense 2 (the choicest or most essential or most vital part of some idea or experience):
center, heart, kernel, marrow, meat, nitty-gritty, nub, pith, substance, sum, inwardness, heart and soulFrom the ODE community, based on WordNetadd/edit