Open English Wordnet
Nouns
(n)kernel, substance, core, center, centre, essence, gist, heart, heart and soul, inwardness, marrow, meat, nub, pith, sum, nitty-grittythe 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”
(n)message, content1, subject matter, substancecontent communicating a message; what something is about
(n)consistency, consistence, substance, bodythe property of holding together and retaining its shape“wool has more body than rayon”, “when the dough has enough consistency it is ready to bake”